U.S. Air Force Research Lab Summer Faculty Fellowship Program

U.S. Air Force Research Lab Summer Faculty Fellowship Program

U.S. Air Force Research Lab Summer Faculty Fellowship Program

AFRL/RQ (Wright-Patterson Air Force Base,, Ohio )

SF.30.23.B10139: Direct Methods for Differential Games

Weintraub, Isaac - 937-255-4459

This research focuses on novel approaches for obtaining differential game solutions where traditional analytic approaches fail. Typical scenarios of interest include separate parties involving one or more agents in opposition. In zero sum differential games, one team strives to minimize some desired performance criteria while the other strives to maximize the same performance criteria. The agents in either team are subject to some path constraints or boundary constraints and their controls may be limited. The dynamics of each of the agents is governed using a set of dynamical equations. Under these many constraints and objectives, the use of numerical tools may be required for obtaining saddle point strategies of both teams. Furthermore, using these numerical tools; the open question remains, "How can one use these numerical tools to obtain the feedback strategies or approximates thereof for implementation?"

The overarching topics of interest for this research effort can be summarized as follows: numerical tools for obtaining solutions to differential games. Extensions for addressing uncertainty, deception, and reduced information are also of interest. Also of interest include methods of taking optimal strategies and approximating those in a feedback manner.

Isaacs, Rufus. Differential games: a mathematical theory with applications to warfare and pursuit, control and optimization. Wiley (1965).

Weintraub, Isaac E., Meir Pachter, and Eloy Garcia. "An introduction to pursuit-evasion differential games." 2020 American Control Conference (ACC). IEEE, 2020.

Weintraub, Isaac E. "Optimal Defense of High Value Airborne Assets." PhD Dissertation, Air Force Institute of Technology, (2021).
Differential Games, Games, Uncertainty, Deception, Multi-Agent, Cooperative, Intelligent Systems, Optimization, Multi-Agent

U.S. Citizens Only

DISTRIBUTION STATEMENT A. Approved for public release: distribution unlimited. (AFRL-2023-3316)

SF.30.23.B10138: Using DNP Assisted NMR to Probe Atomic Structure and Coordination of Metal-Support Interface on Single-site and Cluster Catalysts

Martin, Kara - 937-255-8492

Development and use of single-atom catalysts (SACs) and atomic metal clusters (<1 nm) are a fast-growing area of research. SACs and sub-nanometer atomic clusters have unique electronic properties and coordination with the support which provide high atom utilization, increased conversion/selectivity, and remarkable stability against deactivation from sintering and fouling. Catalyst structure at the atomistic level provides detailed understanding of the catalyst function and permits specificity to catalyst design and optimization. Furthermore, experimental evidence of structure and coordination of the metal-support interface provides the needed insight to model specific catalytic materials and chemistries of interest to a high degree of certainty.

The research opportunity will utilize AFRL’s in-house 400MHz NMR with EIK-DNP capability to characterize commercial and in-house synthesized catalysts to determine bonding and coordination of catalyst support structures with and without SACs and atomic metal clusters. The goal will be to determine a holistic view of the catalyst reactive surface by combining NMR results with existing knowledge of size and electronic properties using material characterization techniques, like STEM and XPS analysis, to eventually develop precise computational models of real catalyst systems with high certainty.

Eligibility: Open to U.S. citizens only

Distribution Statement A: Approved for Public Release; Distribution is Unlimited. PA# AFRL-2023-5240

SF.30.22.B10100: Direct-Expansion Cold Plate Thermal Systems Control Techniques for UAS Aircraft Applications

Roman, Abdeel - 937-604-6905

Future Autonomous Collaboration Platforms will need non-conventional aircraft thermal management systems to remove challenging heat loads. Historically, Unmanned Aircraft thermal management systems have relied on a combination of ram air and single-phase loops for cooling aircraft systems. However, next-generation UAS aircraft power electronics may cause these thermal systems to become inadequate.

The traditional approach to cooling electronic devices for aircraft applications is to chill a single-phase liquid, often using an air cycle machine (ACM). This chilled liquid is then used to cool the electronics via a single-phase cold plate. However, the ACM used to chill the fluid is typically operated by bleeding high-pressure air off the engine compressor, which is an expensive source of energy for powering the thermal management system (TMS), and probably not available for Class 4-5 UAVs. An alternative is to use a vapor compression refrigeration system (VCS) to chill the liquid. AFRL is exploring the use of Miniature Vapor Cycle Systems (mVCS) for managing heat loads on future Unmanned Air Vehicles

However, size, weight, and power (SWaP) requirements on UAVs necessitate the consideration of alternate thermal architectures for implementing a mVCS. Using a direct-expansion cold plate (DXCP) for cooling electronics using refrigerant is a well-favored alternative. This approach has the potential to provide several advantages, including reducing the SWaP required by eliminating the single-phase pumps, plumbing, heat exchangers, and fluid inventory. Yet, using a DXCP as an evaporator on a mVCS has some challenges that need to be overcome. A DXCP is often designed to operate with a certain amount of liquid at the exit to avoid dry-out conditions and improve isothermality. This amount of liquid at the exit of the cold plate could damage a compressor if it is not vaporized. Further, the controls for utilizing a DXCP in a VCS are not well-understood.

This work aims to develop a control methodology for parallel DXCPs that comprise the characterization of a novel control methodology for controlling DXCP on a mVCS with the intent of maintaining a constant mean surface temperature during transient heat loads. The scope of this work includes but is not limited to the study of cold plates with different geometries, CFD analysis, System Modeling and Simulation, validation of the controls methodology, and determining a methodology for predicting the exit quality of the DXCPs.

Research Classification/Restrictions: Open to U.S. citizens only.

SAF PA Review: Case Number: OPSEC-PR-366

SF.30.22.B10095: Operations Research Problem Solving - Agent Collaborative Autonomy

Evans, Dakota - 937-212-7828

The future of collaborative UAV autonomy to achieve level 5 - fully autonomous (Wang, 2021) mission execution without any operator intervention or operator monitoring will require technology advancements in AI-based autonomy. More advanced AI is critical for contested or denied environments where it's unworkable to reach back to human authority to direct or control mission execution. It will be advantageous to have intelligent autonomous systems that conduct themselves similar to operations research analysts such that they can identify opportunities to solve decision problems, estimate the utility and applicability of various solving methodologies, and formulate solutions.

This pursuit aspires to research and develop flexible collaborative autonomy that can solve many different decision problems in mission using a choice space of solving methodologies. This project focuses on a research challenge of developing agent-based autonomy that can emulate the operations research problem solving process for solving decision problems (Jensen, 2002, p. 3). Benefits to the AF include: a.) more intelligent and adaptable collaborative autonomy; b.) capabilities that could enable mission operations that are unattainable with the technologies of today.

Fellowship performers will participate in the following activities: a.) Literature review of operations research methods, multi-criteria decision making, and autonomous systems; b.) application of model-based product line engineering to capture autonomy choice (Young, 2017); c.) Investigation of symbolic and sub-symbolic AI solutions to autonomy problems; d.) software prototyping of operations research analyst agents that can solve sets of military relevant mission management decision problems.

Jensen, P. A., & Bard, J. F. (2002). Operations research models and methods. John Wiley & Sons.
Wang, J., Huang, H., Li, K., & Li, J. (2021). Towards the unified principles for level 5 autonomous vehicles. Engineering, 7(9), 1313-1325.
Young, B., Cheatwood, J., Peterson, T., Flores, R., & Clements, P. (2017, September). Product line engineering meets model based engineering in the defense and automotive industries. In Proceedings of the 21st International Systems and Software Product Line Conference-Volume A (pp. 175-179).

Keywords: autonomy, artificial intelligence, operations research, product line engineering, combinatorics, multi-criteria decision analysis, feature model

Cleared for public release. AFRL/RQ 22-OPSEC-PR-209

SF.30.22.B10072: Structural Design and Analysis Methodologies for Future Force Design

Woods, Daniel - 937-656-8749

The combination of an ongoing revolution in emerging technologies, such as artificial intelligence, and increasingly hostile adversary intentions has ensured a current and future threat environment that is fundamentally different from that of recent decades. Crucially, the present slow timescales and high acquisition costs for the development of new capabilities cannot successfully meet these new challenges and, in many cases, are even counterproductive for national defense. As such, in the context of aerospace structural technologies, there is a need for rapid, cost-effective design iteration and fabrication, as well as a need to accommodate future autonomous battle networks and nontraditional air vehicle concepts. To this end, associated research efforts should emphasize design process automation, low-cost design and fabrication, and compatibility with emerging manufacturing processes and future systems with extensive onboard computing.

Areas of interest include, but are not limited to,

(1) reduced-order modeling of static and dynamic stress distributions, with computational efficiencies suitable for use in multidisciplinary design optimization (MDO);
(2) multi-fidelity structural geometric representation and interpretation;
(3) tailored reformulation of analytical structural mechanics systems under novel design assumptions and specific requirements;
(4) structural layout and topology optimization;
(5) approaches to AI-assisted structural design and analysis;
(6) efficient modeling techniques for anisotropic and nonhomogeneous materials, such as for additive manufacturing (AM) technologies;
(7) incorporation of manufacturability in early design, potentially including generic or process-specific constraints; and
(8) modal and aeroelastic design of complex systems, including for multifunctional, computation-intensive, and potentially interlocking or modular platforms.

PA Case Number: AFRL-2022-3621

SF.30.22.B10071: Neural-Symbolic Artificial Intelligence

Douglass, Scott - 937-938-4600

Symbolic reasoning and machine learning (ML) are different enabling technologies that can be employed by AI-based autonomous systems. Each technology has strengths and weaknesses. ML systems struggle to reason about domain knowledge and explain decisions. Symbolic reasoning systems struggle to learn and reason about unfamiliar events and objects. Growing awareness of these weaknesses is motivating AI researchers to investigate neural-symbolic AI combining symbolic and sub-symbolic processes.

This project centers on the research challenge of developing AI technologies combining the strengths of neural and symbolic processes (Hitzler, 2022). Neural-symbolic AI technologies resulting from this project will enable AF autonomy to: a) learn from the environment; b) reason about what’s been learned. Resulting neural-symbolic AI will also allow AF autonomy to explain actions and decisions.

R&D activities in the project will include: a) reviewing of contemporary neural-symbolic AI R&D (Garcez, 2022); b) modeling action selection using declarative/symbolic languages (Abels, 2021); c) investigating how domain knowledge can be exploited during machine learning by integrating neural networks into answer set programming (Yang, 2020).


Abels, D., Jordi, J., Ostrowski, M., Schaub, T., Toletti, A., & Wanko, P. (2021). Train scheduling with hybrid answer set programming. Theory and Practice of Logic Programming, 21(3), 317-347.

Garcez, A. D. A., Bader, S., Bowman, H., Lamb, L. C., de Penning, L., Illuminoo, B. V., ... & Gerson Zaverucha, C. O. P. P. E. (2022). Neural-symbolic learning and reasoning: A survey and interpretation. Neuro-Symbolic Artificial Intelligence: The State of the Art, 342, 1.

Hitzler, P. (2022). Neuro-Symbolic Artificial Intelligence: The State of the Art.

Yang, Z., Ishay, A., & Lee, J. (2020, July). Neurasp: Embracing neural networks into answer set programming. In 29th International Joint Conference on Artificial Intelligence (IJCAI 2020).

Keywords: autonomy, artificial intelligence, symbolic, sub-symbolic, neural-symbolic integration, neural networks, answer set programming.

PA Case Number: AFRL-2022-3361

SF.30.21.B10039: Two Phase Thermal Systems Control Techniques for UAS Aircraft Applications

Roman, Abdeel - 937-713-3169

The thermal management architecture of UAV electronic packaging needs to be significantly stretched to meet size, weight and power (SWaP) requirements. As the number of electrical systems increases on a UAV application, their physical size decrease, and the spacing between electrical components decreases. Thus, the power density and the total amount of heat generated increase significantly. Current heat transfer systems used in UAV are asymptotically approaching their limits imposed by available cooling area, available air flow rates and fan power.

High power electrical components used in UAS applications can be more efficiently cooled using two phase cold plates. Some devices need to be held at a very uniform temperature with very small temporal variations which means over-cooling degrades performance just as under-cooling. The temperature can be controlled by modulating the refrigerant mass flow rate and cold plate saturation pressure but these are influenced by the thermal management system as a system not just particular components in the system. The goal of the study is to develop control techniques and algorithms that maintain device temperature in the presence of large swings in thermal load or heat sink conditions.

Restrictions: Open to U.S. citizens only.

PA Review: Case Number: AFRL-2021-3122

SF.30.21.B10036: Development and Application of Research Tools for High-Speed Air-Breathing Propulsion

Hammack, Stephen - 937-255-9242

Development of high-speed air-breathing propulsion is contingent upon an improved understanding of the fundamental processes that govern engine operability and performance. The challenges of obtaining high-quality and thorough measurements in high-speed reactive flows requires advancements in non-intrusive diagnostics and innovative applications. The ability to understand, model, and predict system behavior is inherently linked to capabilities and limitations in flow path interrogation. As such, the scope of this program includes efforts focused on diagnostics, supersonic flow path measurement, and/or CFD tool development. For example, objectives might include one or more of the following:
• Advancement of diagnostic fidelity and/or technical maturity
• Development of new diagnostic capabilities or innovative implementation,
• Development of numerical models and tools,
• Experimentation and data analysis to study relevant phenomena and/or validate models.

Proposed activity should align with topics of interest, either directly (measurements, analysis, modeling) or indirectly (development of relevant diagnostic and numerical tools). Topics of interest include ignition and stability, fuel injection and distribution, and flow path response and control.

The development of experimental approaches often begins in laboratory space using small-scale flow paths, burners, and pressure vessels before transitioning to the supersonic wind-tunnel research cells. Facilities at WPAFB include a variety of wind-tunnels (including direct-connect scramjet tunnels) and optics/combustion laboratories, a wide range of laser and imaging equipment (including high-speed assets), and computational resources.

Eligibility: Open to U.S. citizens only

Case Number: AFRL-2021-2803

SF.30.21.B10034: Durability and Damage Tolerance Assessment of Bonded Unitized Composite Structures

Ranatunga, Vipul - 937-656-8809

Affordable certification of bonded unitized composite structures is critical for effective development of efficient advanced structural concepts for next generation US Air Force aircraft systems. The Aerospace Systems Directorate, Air Vehicles division is open to cultivate research collaborations with the academic community and advance the state-of-the-art in analysis tools for durability and damage tolerance assessment of bonded unitized composite structures.

Basic research in developing efficient and accurate analysis methods which are capable of modeling damage in large structures is needed to eliminate the heavy dependence on building-block testing for structural validation. Following are the most sought-after research ideas, but the offeror may propose novel areas for studies that may aid in developing technologies for bonded unitized structures.

(I). Development of analysis approaches for predicting damage initiation, growth and final failure due to static loading. The ability to predict the static compression strength in the presence of impact damage, accurate representation of interactions with damage arrestment features such as fasteners, stitches, or pins, and the possibility of implementing the analysis methodology in shell-element formulation for efficient structural analysis are some of the important considerations for a static analysis tool.

(II). Development of fundamental structural mechanics to accurately capture the damage and failure during an impact event, particularly when the damage is primarily matrix cracking and interlaminar delaminations. The incorporation of strain-rate sensitive damage mechanics in an efficient finite element formulation, the ability to model an entire structure efficiently while capturing the most predominant damage mechanics, efficient implementation in a finite element framework for global-local analysis, are some of the challenges encountered by the research community.

(III). Development of novel experimental methods for generating fracture, strength, and stiffness properties under elevated loading rates, enhanced nondestructive evaluation techniques for field assessment of impact damage, efficient methods for damage representation and transfer between explicit and implicit analysis methods, will be vital for the advancement of tools for affordable certification.

(IV). Development and implementation of basic structural mechanics to simulate the damage initiation, propagation, and final failure due to cyclic loading. The proposed methods should consider the presence of impact damage and the damage arrestment features mentioned previously.

Keywords: Impact Damage, Delamination, Finite Element Modeling, durability & damage tolerance, composite structures, Barely Visible Impact Damage.

Cleared for public release. AFRL-2021-2948

SF.30.21.B10033: Advanced Propeller, Rotor, and Fan Fluid Dynamics Design Integration

Roth, Gregory - 937-713-6658

Recent advances in uninhabited aerial systems, autonomous air vehicles, drones, the urban air mobility movement, and a greater emphasis on flexibility in mission capabilities has driven more employment of propeller, rotor, and fan driven concepts in recent years. A better understanding of the effects and potential of these propulsion systems and their integrated effects applied to flight systems could enable the development of revolutionary vehicle configurations for missions that incorporate vertical operations, distributed propulsion, and coupled fluid dynamics, among others. Exploring the possible benefits of advanced propellers, rotors, and fans for Air Force missions requires a full understanding of the multidisciplinary effects of aerodynamics, propulsion, structural mechanics, flight dynamics, aeroelasticity, multiple energy sources, and dissipation of unused energy, often as thermal loads.

A wide breadth of mission capabilities are enabled when all available propulsors are considered. Collaboration with propulsion subject matter experts (SMEs), power and control SMEs, aero-performance SMEs, as well as aerospace vehicle SMEs will ensure the most effective air vehicle system is synthesized based on mission requirements. The core objective is to enable the application of multidisciplinary, multi-fidelity, design and analysis to achieve optimal effectiveness for eVTOL, runway independence, HSVTOL, and HALE/MALE type missions with attention given to acoustics, distributed propulsion, engine/motor/gearbox matching, coaxial designs, airframe integration, propeller wake/wing boundary layer interactions, blade vortex interaction, and shrouded/ducted designs where applicable.

Opportunities for propeller/rotor/fan focused research include, but are not limited to: balance of conflicting mission or vehicle requirements from coupled subsystems, goal oriented design approaches, reduced order models, machine learning, enhanced design creativity, flow control for improved efficiency, acoustics modeling, nonlinear and coupled effects, blade dynamic responses, additive manufacturing of composite blades for ground and flight test, sensitivity analysis/adjoint approaches, uncertainty quantification leveraging non-deterministic or stochastic methods, and experimental testing to build trust in computational models. Specific applications of actuator disk (axial momentum) theory, blade element momentum theory (BEMT), lifting line/vortex lattice approximations, Euler based methods, Large Eddy Simulation (LES), Reynolds Averaged Navier-Stokes (RANS) methods, and Lattice-Boltzmann approaches are all applicable as well as experimental wind tunnel studies and flight tests.

Keywords: propellers, rotors, fans, ducted, distributed propulsion, electric / hybrid propulsion, blade element momentum, BEMT, eVTOL, HSVTOL, UAV, autonomous air vehicles, vortex, BVI, machine learning, multidisciplinary, flow control, design, creativity, decision making, mission effectiveness.

Security and citizenship requirements determined on a case by case basis depending on specifics of research conducted and application to current systems.

Cleared for public release. AFRL-2021-2890

SF.30.21.B0004: Studies of Rotating Detonation Engines and Underlying Science for Airbreathing Propulsion

Fievisohn, Rob - 937-656-4100

Rotating Detonation Engines (RDE) use a rotating detonation wave to rapidly compress propellants and release heat at high pressure. By releasing heat a high pressures greater thermo-dynamic efficiencies can be achieved compared to conventional deflagration based engines using the same level of pre combustion mechanical compression. In addition using detonation based combustion results in extremely compact combustors which has significant advantages in volume limited systems. Because of these advantages AFRL is investigating RDEs for a range of applications. This research addresses the underlying physical processes that occur in an RDE including detonation propagation limits, propellant mixing, injector aerodynamics, heat release, heat transfer, materials, detonation dynamics, novel fuels and the methods to measure these time varying physical process via advanced diagnostics. Innovative experimental, computational fluid dynamics, system analysis, and reduced order modeling approaches to understand and quantifying these phenomena are desired. A number of well-equipped laboratories are available to carry out detonation experiments ranging from small detonation tubes to full scale RDEs at flight relevant conditions. A host of advanced laser diagnostic capabilities are available. Access to various computational fluid dynamic codes and computational hours are available through the DOD ASC Major Shared Resource Center.
Eligibility: Open to U.S. citizens only
Distribution Statement A: Approved for Public release; distribution is unlimited. Case Number: 88ABW-2020-2951

SF.30.21.B0003: Realizing Aeroservoelastic Adaptivity

Pankonien, Alexander - 937-713-7136

Explore the “art of the possible” in aircraft-relevant Adaptive Structures that mitigate or leverage linear and/or nonlinear aero-servo-elastic phenomena and their associated rapid, robust, cost effective experimental investigation. To enable this paradigm requires not just novel design and analysis techniques but also novel sensors, novel “computational” mechanisms (including nonlinear metastructures / metamaterials / structural computing), and novel actuation schemes. These sensing components should improve the real-time observability of the relevant flow and structural states of the adapting components or vehicle, while the actuation components should provide the appropriate adaptivity modalities and timescales to harness the associated interactions between flow, structure and rigid body inertia without overburdening weight or system weight and power requirements. Advances in additive manufacturing should also be appropriately leveraged, ranging from the conceptual design level including topology and its parameterization through practical considerations that expose limitations in the current state of the art. Special consideration will be given for bridging the divide between prediction and experiment, including the efficient exchange of information between the two for relevant problems in order to: use predictions to design a better experiment, extend results beyond the range of achievable experimentation, or use experiments to better calibrate predictions.

SF.30.21.B0002: Aerodynamics of High-Performance Inlet Systems for Air-Breathing Propulsion

Benton, Stuart - 937-713-6695

Future aerospace systems will span a wide range of speed and size classes. Each aircraft concept places a unique set of requirements on the integration of a high-performance inlet to feed air to the gas turbine engine. In our research group we seek to combine low-cost experimental testing with modern computational analysis to gain a better understanding of the flow field and enable advanced inlet concepts through a design, analyze, build, and test methodology. This research area covers the design and analysis of inlet systems for subsonic through supersonic applications. Aerodynamics of separated flow in diffusing internal ducts and shockwave boundary layer interactions are featured prominently in unsteady and three-dimensional configurations. Practical approaches to the use of computational fluid dynamics which enables the minimum fidelity required for successful prediction of total pressure recovery and flow distortion are needed to evaluate new inlet systems and explore aerodynamic flow control. This includes the use of hybrid RANS/LES techniques to compute unsteady characteristics of the distorted flow field at the fan/compressor interface.
Topics of interest include:
(1) efficient simulation of supersonic inlets, including modelling of boundary layer bleed and inlet starting procedures,
(2) hybrid RANS/LES of inlet systems with a focus on prediction of peak unsteady inlet distortion,
(3) novel flow control approaches applied to inlet flow fields,
(4) effects of forebody integration as well as off-design speed and incidence on inlet performance,
(5) experimental approaches to generate flow distortions which mimic the downstream influence of various components of the inlet system,
(6) statistical approaches for the reduction of computational and experimental data related to post-processing engine-face distortion patterns,
(7) systems-level analysis of gas-turbine installation effects on aircraft and/or engine performance.

SF.30.21.B0001: Design, Optimization, Characterization, Application, and Demonstration of Smart Materials and Morphing Structures in Aerospace Systems

Beblo, Richard - 937-713-7133

Aircraft designers are constantly searching for technologies, tools, and methods to expand the flight envelope and mission effectiveness of modern air vehicles. Smart materials and morphing technologies accomplish this by providing the vehicle a way to adapt to changing environments and demands resulting in a more capable, versatile aircraft. Often, however, these technologies fail to transition to fielded systems due to decreased performance when integrated into real systems. Multidisciplinary analysis and optimization (MDAO) can assist in raising the technology readiness level of many of these technologies by analyzing their impact at a system level. Multidisciplinary experimental characterization is then required to validate these multidisciplinary analysis methods. Clever informed design from validated methods at the conceptual level can often mitigate negative system level interaction of a technology post integration. Research topics of interest include (1) morphing/reconfigurable structures technologies; (2) novel methods of system level morphing technology design and optimization methods; (3) system level morphing structures analysis methods; (4) experimental morphing structures characterization; (5) multidisciplinary experimental testing; (6) smart material applications research; (7) smart material modeling techniques; and (8) multiscale material modeling and applications.

SF.30.20.B0001: Unmanned Aircraft Systems Propulsion Development

Fernelius, Mark - 937-713-0047

The Small Engine Research Laboratory (SERL) explores and develops propulsion systems for military unmanned aircraft systems (UAS). These propulsion systems include piston and turbine engines. The unique challenges at small scales make it difficult to simply scale down large propulsion systems. Both turbine and piston engines become less efficient as they become smaller in size. The SERL investigates ways to increase the performance of these small systems. Performance can be defined in terms such as system cost, power density, efficiency, reliability, or endurance. The SERL investigates novel concepts for UAS propulsion. These concepts could be an entire new propulsion system, a modification to an existing system, or an addition to an existing system.
The main objective of this topic is to increase the performance of propulsion systems for military UAS. Research can include both computational and experimental efforts. Laboratory facilities are able to run both piston and gas turbine engines, including at sub-atmospheric conditions. A wide range of instrumentation and diagnostics are used to measure engine operating parameters. This includes both intrusive and non-intrusive diagnostic capabilities.

SF.30.19.B0007: Basic Research in Energy and Combustion Science

Rankin, Brent - 937-255-9722

Improving fundamental understanding of turbulent combustion in relevant regimes is important for many power and propulsion applications with significant impact and broad relevance to a range of national and international grand challenges. The grand challenges include achieving a sustainable energy future through increasing efficiencies of power, propulsion, and transportation systems; attaining a clean environment through managing pollutant emissions; and enhancing national security through pursuing innovative defense technologies. Power and propulsion systems which rely upon turbulent combustion are pervasive across the Department of Defense and United States Air Force for current and next-generation applications such as gas turbine combustors, inter-turbine combustors, augmentors, rotating detonation engines, scramjets, and rockets.
The primary objective associated with this topic involves performing basic research or advanced technology development related to the broad areas of energy and combustion science. The experimental or computational work should focus on relevant configurations operating under relevant conditions. Specific turbulent reacting flows of interest include swirl stabilized flames, cavity stabilized flames, bluff-body stabilized flames, and detonations. Relevant conditions typically involve high pressures, high temperatures, high speed compressible flows (i.e. high Mach numbers), high turbulence intensities (i.e. high Reynolds numbers), and multi-component liquid fuels. Research opportunities include but are not limited to the following general topics: (1) fundamental interactions between turbulence, chemical kinetics, flame structure, and flame dynamics; (2) near-limit combustion phenomena such as ignition, extinction, and thermo-acoustic instabilities; (3) advanced combustion technologies for enhancing ignition under low-pressure low-temperature conditions, improving flame stabilization in high-speed compressible flows, or minimizing thermo-acoustic instabilities; (4) spray combustion of multi-component liquid fuels; (5) combustion modeling and simulation; and (6) thermodynamic cycle analyses.
The research and development is expected to align with ongoing work being conducted at the Air Force Research Laboratory Aerospace Systems Directorate Turbine Engine Division Combustion Branch. The Combustion Branch provides access to state-of-the-art experimental and computational resources including the Combustion Research Complex, High Pressure Combustion Research Facility, and Supercomputing Resource Center. The experimental facilities are capable of supplying large amounts of air and fuel at the pressures, temperatures, and flow rates necessary to achieve relevant conditions in representative single-element benchmark configurations. Experimental capabilities include but are not limited to emissions sampling; hot-wire anemometry; high-speed broadband, filtered chemiluminescence, and mid-infrared imaging; hydroxyl and formaldehyde planar laser induced fluorescence (PLIF) imaging; particle image velocimetry (PIV); and phase Doppler particle anemometry (PDPA). Computational capabilities include in-house and commercial large eddy simulation (LES) codes and high-performance computing (HPC) systems.
Keywords: Combustion; Detonation; Propulsion; Power generation; Combustion experiments; Combustion modeling; Computational fluid dynamics (CFD); Large eddy simulations (LES); Gas turbine engines; Inter-turbine combustors; Augmentors; Afterburners; Rotating detonation engines (RDE)

SF.30.19.B0006: Full-scale Jet Noise Prediction

Giese, Alex - (937)255-1443

Under the Advanced Turbine Technologies for Affordable Mission-Capabilities (ATTAM) program, the Aerospace Systems Directorate (AFRL/RQ) is researching technologies that will form the basis for the next generation of high performance fighter jet engines. However, increased engine performance does come at a cost: increased noise exposure to warfighters. For example, a concern is the noise-induced hearing loss suffered by servicemen who work in close proximity to aircraft, such as on the deck of an aircraft carrier. The Department of Veteran’s Affairs estimates that it will spend in excess of $4B in compensation to veterans for hearing-related disabilities in 2015 (1), with this number increasing every year. The ability to predict jet-engine related noise for military systems would provide increased capability and flexibility for future defense acquisition program.
For decades, the DoD has spent millions of dollars measuring jet noise emissions from numerous military aircraft. Past studies have employed these measurements and developed physical and computational models in an attempt to scale-up model-scale jet-noise prediction tools to full-scale jet engines. These studies have resulted in valuable enhancement of our understanding of physical jet noise mechanisms, but to date have not been shown to successfully predict noise emissions for a full-scale engine. The Human Effectiveness Directorate (AFRL/RH) and its predecessor organizations, over several decades, have measured and amassed the most comprehensive dataset of supersonic jet engine noise anywhere in the United States. For the first time ever, full-scale acoustics and flow data are available to achieve an engine-noise prediction model designed to inform engine design parameters in the initial planning stages.
Under the 2019 SFFP, the following research objectives will be considered to initialize the development of this capability.
• Synthesis of existing supersonic jet engine data into a single database for easy analysis
• Parametric investigation to correlate engine performance to noise emissions
• Special considerations for exhaust nozzle configuration
• Formulation of an initial predictive engine noise model
• Recommendations for further noise and engine exhaust flow measurements to increase predictive capability
(1) U.S. Department of Veterans Affairs, “Compensation,” Version 1.0, May 2016

SF.30.19.B0005: Unsteady Aerodynamics

Medina, Albert - (937) 713-6669

A thorough understanding of unsteady aerodynamics is critical when analyzing and designing aircraft operating in unsteady flight environments or undergoing maneuvers; wind energy devices; rotorcraft; and aircraft during takeoff and landing. Accurate knowledge of the underlying flow physics that occur during unsteady conditions would allow for the determination of aircraft performance and design requirements when operating near the boundaries of the flight envelope, but further research is required to determine the dynamic response of aircraft to unsteady incoming flow fields and vortex-dominated wakes. Analytical methods, numerical simulations, and experimental studies are all useful in their contributions to improve the overall body of knowledge. The current focus is on incompressible studies involving dynamically pitching, plunging, and/or surging wings with or without the incorporation of flow control. The ultimate goal of this body of research is a robust low-order model of the complete vehicle state which could then be used for flight performance determination, closed-loop control, and vehicle design.

Areas of interest include, but are not limited to: (1) Gust mitigation/rejection with or without flow control, (2) maintaining control surface effectiveness during extreme maneuvers, (3) reduced-order modeling of vortex-wing interactions, (4) dynamic stall characterization and prevention, (5) load response of wings interacting with unsteady flow fields, (6) mitigation of separated flows using flow control, (7) development of closed-loop control algorithms, and (8) development of flow control devices.

SF.30.19.B0003: Intelligent Power Systems for Next Generation Aircraft

Fellner, Joseph - (937) 255-4225

DC aviation Electrical Power Systems (EPS) provide many advantages, particularly in the area of weight savings and increased efficiency. Despite these advantages, there are technical challenges that need to be addressed as the power and dynamic response demanded by more-electric loads increase. High power DC systems require low source impedance which makes larger fault energy available to the system. In addition, flight and mission critical loads demand constant power and fast response which can cause dynamically negative resistance resulting in poor power quality and/or loss of system stability. AFRL’s objective is to develop an intelligent power system to advance the state of the art in system efficiency, safety, power management, power stability and quality. Advances of new technologies in power electronics, energy storage, and communication and control theory create new opportunities in the design of intelligent power systems for mission critical purposes that can tackle these challenges. The following areas of research are of interest: 1) Intelligent and novel generator and energy storage design and control strategies, 2) New power electronics and control techniques to source 270 and +/- 270 Vdc, 3) Intelligent methods for fault detection, localization, and isolation including series arc, 4) Optimal power management strategies utilizing modern optimization techniques, 5) Stability analysis and control strategies to mitigate impacts of constant power loads and increase power quality, 6) Mechanical/electrical modeling and simulation, and 7) Hardware in the Loop (HIL) strategies including Control HIL and Power HIL. 8.) Characterization and evaluation of wide bandgap semiconductors for aviation based power electronics, and 9.) Measurement, Modeling, and Mitigation strategies for conducted electromagnetic interference.
Keywords: Power systems, power electronics, stability analysis, optimal control, hardware in the loop

SF.30.19.B0001: Development of Analytical Methods for Enhanced Understanding of Aviation Fuel Composition

Wrzesinski, Paul - 937-255-4867

The bulk composition of aviation fuel consists primarily of hydrocarbon species: n-paraffins, isoparaffins, cycloparaffins, and aromatics. However, fuels are also known to contain heteroatomic compounds containing nitrogen, oxygen, and sulfur in trace amounts. The detection and quantification of these compounds is of interest to the aviation fuels community, as these trace species can have significant impact on fuel properties and the ability to meet specification requirements. Of particular interest are experimental methods that can isolate the trace compounds from the bulk matrix, identify the compounds functional groups and molecular formula, as well as, provide quantitative data. The goal of this research is to develop new analytical techniques or data processing tools that allow for better elucidation of the trace components present in aviation fuel. Furthermore, the ability to accurately and reproducibly obtain quantitative results is of interest. Current fuels, whether derived from traditional crude or other sources such as oil shale and tar sands are included in this research, along with alternative fuels (those derived from non-petroleum sources). Cleared for Public Release: Case Number 88ABW-2020-2355 Eligibility: Open to U.S. citizens

SF.30.18.B0001: Analysis Tool to Predict the Behavior of Bolted Composite/Metallic laminate Joints

Gran, Mike - (937) 656-8823

The goal is to develop a validated analysis tool to determine the fastener load distributions and stress/strain fields in a bolted structural joint made up of laminates consisting of interleaved carbon fiber reinforced polymer layers and thin metallic layers. The analysis tool must account for the contact phenomenon and the interaction among the bolts explicitly under bearing and by-pass loading without restrictions on the nature of the composite/metallic laminate and the type of loading.

Bolted joints are unavoidable in the construction of composite structures which require disassembly for inspection or maintenance. The main disadvantage of bolted joints is the formation of high stress concentration zones at the locations of bolt holes, which might lead to a failure of the joint due to net-section, shear-out, or bearing failures, or combinations thereof. The deformation, damage, and degradation of laminated bolted joints consisting of interleaved composite and metallic lamina must be understood in order to improve the bearing properties of composite materials. Understanding the behavior of a bolted joint can result in weight and cost savings by designing against unnecessary conservatism. With aircraft containing numerous conventional bolted composite joints, it would be beneficial to be able to more accurately predict damage propagation and degradation over time to enable increased inspection efficiency and ensure structural integrity throughout, and potentially beyond, the aircraft’s expected service life. Extending this characterization to composite/metallic laminates will then help provide the potential for that technology to be applied to future aircraft designs.

Areas of interest include (1) degradation in material stiffness (2) through thickness stress variation (3) non-linear bearing deformation (4) progressive failure analysis and (5) optimization for bearing strength of composite/metallic laminate layup.

KEYWORDS: Semi-analytical, bolts, composites, hybrid laminates, lap joints, contact stresses, hole elongation

SF.30.17.B0006: Application of Similarity Laws in High Speed Viscous Flows

Miller, James - 937-255-7212

Complex flowfield interaction regions, caused by control surface deflections, wing-body junctures, structural gaps, or large angles of attack, often become design drivers for high speed vehicles. Recent research in AFRL has demonstrated a more practical approach to characterizing these regions, which are usually characterized by shock interactions that cause large pressure gradients to exist in the vicinity of viscous boundary layer flows. With AFRL’s discovery of a new similarity parameter for the Navier-Stokes equations that represents the ratio of pressure forces to viscous forces, it is now appropriate to explore analytical approaches to characterizing external flows with bounding values of this new parameter. For example, viscous flow regimes that could be explored include flows that are dominated by large pressure forces, but small viscous forces; or have small pressure forces but are dominated by large viscous forces. In addition it may now be possible to fruitfully explore closure equations for turbulent flows and develop new closed-form approximations to the Navier-Stokes equations. With the intent of focusing on high speed flows, the present research opportunity hopes to address research questions as follows (listed in priority order): 1) Explore the impact of pressure force / viscous force ratio on existing boundary layer theories, with eventual application to high speed external viscous flows including computational results and experimental measurements 2) Explore feasibility of pressure force / viscous force ratios to developing turbulence models to close the Reynolds stress equations either through turbulent viscosity models or stress-equation models for high speed viscous flows. 3) Explore basic physics of shock / boundary layer interactions or 3D viscous interactions to characterize ratios of pressure forces / viscous forces for fundamental fluid interactions using LES or DNS methods. This could include exploring the feasibility of improving filtering methods for LES/DNS using the aforementioned pressure / viscous considerations.

SF.30.17.B0005: Advanced Aeronautical Design Methodologies

Kao, Jason - (937) 713-7152

Advanced design space exploration and optimization technologies enable development of potentially revolutionary vehicle configurations for Air Force needs. But progress is contingent upon synthesis of design tools, engineering level aerodynamic analysis tools, and the associated disciplines of wind tunnel testing and traditional computation. A wide range of mission areas and vehicle concepts is of interest, including: small UAS, air dominance, long dwell ISR, tankers, transports, UCAVs, and VTOL.

In the design space exploration area, research-interests include Multidisciplinary Design Optimization (MDO), creativity and ideation, bio-inspired design methodologies, and design leveraging artificial intelligence/machine learning.

Vehicle design and configuration maturation topics of interest include: geometric definition of unconventional vehicle configurations or topologies, coupled analyses for unconventional vehicle geometries, integration of large diameter propulsors, distributed propulsion, rapid geometry and mesh generation, unconventional power and propulsion integration (hybrid/electric vehicles), structural layout, performance modeling, mass properties estimation, etc.

Partners are sought to conduct practical analyses, develop tools and methods, research configurations and multidisciplinary coupling phenomena, and design exploratory campaigns linking wind tunnel testing and computation.

Keywords: conceptual design, creativity, ideation, MDO, unconventional configurations

SF.30.17.B0003: Machine Learning Approaches in Computational Fluid Dynamics

Schrock, Christopher - (937)713-7138

Machine learning (ML) approaches have become commonplace in many technical fields, however, their exploration, adoption, and exploitation in the areas of computational fluid dynamics (CFD), fluid modeling, and aircraft design is still an area of emerging research. Promising initial efforts have demonstrated the methods effectiveness in expanding the accuracy of Reynolds Averaged Navier Stokes (RANS) methodologies to flows for which such methods typically exhibit poor performance. While such methods have shown initial promise, a challenge remains in determining proper methods for infusing computational and experimental training data while satisfying physical constraints. Others have begun to apply similar techniques to multifidelity approximation of flows, CFD solver convergence acceleration, and reduced order modeling. Application of such techniques could hold promise in reducing computational expense of standard CFD approaches, reducing man-in-the-loop demands in mesh generation, providing for rapid aerodynamic estimates by providing a framework for assimilating large amounts of computational parametric data, expanding validity of physical models, and assisting in solver characterization among other possibilities. This topic envisions supporting continued exploration of such methods and their application in CFD. Some areas of particular interest are: (1) Development of ML-based or corrected turbulence models, (2) Convergence acceleration via ML approximations, (3) Development of ML based rapid aerodynamic prediction capability based on parametric computational simulations, (4) ML assisted grid generation, and (5) ML based characterization of solver performance.

SF.30.17.B0002: Fan and Compressor Aerodynamics Design and Analysis

List, Michael - (937) 255-7047

Aerodynamic design and analysis of modern compression systems uses meanline, throughflow, and CFD to generate flowpath and airfoil shapes. The Compressor Aero Research Lab (CARL) investigates gas turbine aero engine fan and compressor aerodynamic/aeromechanic performance to impact future designs. CARL is developing meanline and throughflow capabilities in-house for design, and CARL applies a range of academic, government, and commercial CFD tools for analysis. Collaboration is possible through implementation of plug-ins – discrete, focused code modules – for everything from loss models to blade parameterization to file exports.

Topics of interest include but are not limited to:

(1) implementation of loss, mixing, and other generally applicable models;
(2) development or implementation of post-processing tools to assess off-design operation, e.g. Gong and Tan model;
(3) novel blade shape parameterization for optimization;
(4) integration with MDAO frameworks;
(5) efficiency improvements in the design-to-CFD process;
(6) early design phase aeromechanics, such as Campbell diagram generation.

U.S. citizenship required.

SF.30.17.B0001: Fan and Compressor Aerodynamics Experimental Research and Data Analysis

List, Michael - (937) 255-7047

Collection and analysis of experimental datasets from transonic fan stages benefits the design and analysis processes of modern fans and compressors. The Compressor Aero Research Lab (CARL) investigates gas turbine aero engine fan and compressor aerodynamic and aeromechanic performance to impact future designs. To support the synthesis of experimental results into design guidance and models, CARL collects high-fidelity experimental datasets and implements / develops state-of-the-art post-processing techniques.

Topics of interest include but are not limited to:

(1) data reduction and analysis techniques for unsteady pressure measurements, including over the-rotor kulites;
(2) stall detection automation;
(3) reduced order modeling, linear and non-linear analysis, and multivariable analysis of complex 3-D flows;
(4) flow feature detection and model development;
(5) assessment of novel and low-intrusion instrumentation and measurement techniques;
(6) experimental planning for design tool calibration and CFD validation;
(7) uncertainty quantification and error analysis;
(8) formulation of generic and calibrated models for assessment of derivative airfoil designs.

U.S. citizenship required.

SF.30.16.B0004: Combustion Stability in High-Speed Flows

Ombrello, Timothy - (937) 656-5950

Presently, the harsh and restrictive reactive environments within high-speed propulsion systems, such as scramjets, can be limiting factors for their development and practical implementation. Typically, these limitations lie in the ability to ignite, propagate, and stabilize a flame near flammability limits, at low temperatures and pressures, and within short residence times. There is a need to better understand the fundamental interactions involved in producing and stabilizing a flame using passive devices (such as strut or cavity flameholders) and active devices (such as energy addition via plasma) across the broad operating range of Mach numbers and dynamic pressures present in expendable and reusable high-speed propulsion platforms. A range of systems are available to interrogate these problems, including simple bench-top experiments (including a variable pressure combustion chamber and linear flow ignition tunnel), to wind-tunnels (including direct-connect scramjet facilities). A host of optical and laser diagnostic assets are available, including, but not limited to planar laser-induced fluorescence (PLIF), particle image velocimetry (PIV), nanosecond-gated laser-induced breakdown spectroscopy (n-LIBS), high-frame-rate UV and visible imaging (up to 10 million frames per second), multi-spectral infrared imaging (up to 90,000 frames per second) and absorption and emission spectroscopy, to study these phenomena.

Keywords: Supersonic combustion; Scramjets; High-speed flows; Plasma; Plasma-assisted combustion; Advanced optical diagnostics; Reactive flow energy coupling

Eligibility: Open to U.S. citizens

SF.30.16.B0003: Extreme Light Matter Interactions

Caswell, Andrew - 937-255-7098

The goal of this program is to gain a fundamental understanding of the interactions of ultra-short pulse, ultra-intense laser (extreme light) interactions with matter. Experimental and computational studies of the interaction of a 10 mJ, 1 kHz, 35 femtosecond pulse laser with micron diameter water jets are being performed. Experimental studies have demonstrated the production of MeV electrons and gamma rays from the interaction of the laser, focused to an intensity of 10^18 W/cm^2, with a 25 um diameter water jet when a significant pre-pulse is present. Simulations of laser/water jet interaction have provided considerable insights into the processes responsible for producing electron and gamma rays and the role of the pre-pulse. Experiments using a laser intensity of 10^19 W/cm^2 and eventually at near-IR wavelengths are being planned. Also, laser/heavy water jet interaction experiments are in preparation to produce neutrons by a laser fusion process. The fundamental understanding gained from these types of experiments will aid in determining the feasibility of using similar types of extreme light/target interactions to produce fundamental particle and radiation as a source for nondestructive inspection of weapon system components. We are interested in faculty and graduate students with experience in conducting or simulating extreme light/target interaction experiments similar to those outlined in this topic.
Keywords: Extreme Light; Femtosecond Lasers; MeV Electron Production; Gamma Ray Production; Laser/Target Interactions
Eligibility: Open to U.S. citizens

SF.30.16.B0001: Control Techniques for Aircraft Energy Management

Hencey, Brandon - (937)-255-0375

Current and next generation of aircraft are faced with increasingly critical power and thermal requirements despite decreasing footprint (i.e. weight, volume, and external sinks). These challenges involve large transient loads and strenuous mission environments. The siloed and steady-state design paradigms have reached a point of diminishing returns for expanding system capabilities. Instead, techniques are needed that dynamically allocate energy resources over the mission and across the aircraft to vastly expand capability. This necessitates coordinating energy conversion, distribution, storage, and dissipation among subsystems. Specifically, there are tremendous opportunities for employing cyber-physical systems concepts applied to power and thermal systems. Potential techniques include optimal control, predictive control, distributed control, Bayesian estimation, formal synthesis, and machine learning.
Keywords: System integration; optimal control, predictive control, distributed control
*Eligibility: Open to U.S. citizens

SF.30.13.B1109: Two Phase Thermal Management

Byrd, Larry - (937) 255-3238

Next generation aircraft have a significant increase in thermal loads due to a transition to more electric aircraft, more powerful electronics, and an increase in the use of the composite structures. Two phase systems for thermal management are becoming more common for these aircraft. This is due to higher heat transfer coefficients and large latent heats that provide near isothermal cooling at much lower mass flow rates than single phase systems. Two phase systems are not without problems however. Flow instabilities, non-uniform flow distribution and a greater sensitivity to aircraft acceleration can result in inadequate cooling. Cavitation in pumps and liquid ingestion in compressors can quickly damage the prime movers in these systems. We are investigating the limitations of two phase thermal management at both the component and system level through modeling and small scale experiments.

Examples of research in this area include:

*Control and stability of two phase systems with transient loads and multiple heat exchangers.

*Optimal system architectures for different classes of aircraft which could include the use of non-standard working fluids such as CO2 and liquid natural gas.

*Hybrid systems that can reject heat at higher temperatures than current refrigerants.

Eligibility: Citizenship: Open to U.S. citizens only.

PA Case Number: AFRL-2022-3462

SF.30.13.B0913: Cooperative Control of Autonomous Systems in Uncertain Information Environments

Casbeer, David - (937) 255-4895

This research focuses on cooperative control problems involving autonomous agents in uncertain environments with communication restrictions. Typical scenarios of interest involve different modalities of communication, e.g., high-bandwidth, high-rate communications for short range peer-to-peer interactions and low-bandwidth, low-rate communications over larger distances. Agents must be able to intelligently adapt to the situation at hand and base decisions on the locally available (and uncertain) information, while still guaranteeing success of the overall mission. To accomplish this, the agents must be able to ascertain what information is important to ensure correct and appropriate decision-making for success of the overall mission objective. Furthermore, with the necessary information for mission success determined, the agents must be able to keep this information accurate and up-to-date given the changing (possibly distributed) communications restrictions. With such systems, analytical tools are needed to guarantee overall mission success given that decision-making is distributed with uncertainty. The overarching topics of interest for this research effort can be summarized as follows: value-of-information, distributed estimation, and distributed decision-making/control.


K. Krishnamoorthy, M. Pachter, S. Darbha, P. Chandler, Optimization of Perimeter Patrol Operations using UAVs, AIAA J. Guidance, Control and Dynamics, 2011.

K. Krishnamoorthy, D. Casbeer, P. Chandler, M. Pachter and S. Darbha, UAV Search & Capture of a Moving Ground Target under Delayed Information, IEEE Conf. Decision and Control, 2012 (to appear).

D. Casbeer, K. Krishnamoorthy, A. Eggert, P. Chandler and M. Pachter, Optimal Search for a Random Moving Intruder, Proc. AIAA Infotech@Aerospace Conf. 2012.


distributed and robust decision-making, (partially-observable) Markov decision process, intelligent control, distributed estimation, sensor fusion, value-of-information, multi-agent


Citizenship: Open to U.S. citizens only.

SF.30.13.B0912: Advanced Structural Concepts for lighter and low-cost Aircraft

Joo, James - 937-656-8759

Modern aircraft have the most efficient aerodynamic shapes ever using advanced tools including Computational Fluid Dynamics (CFD). Aircraft structures and materials technologies have also developed over a hundred years since the first flight, but structural design concepts haven’t developed as quickly. Many decades-old technologies are still widely used for substructure construction, which is composed of orthogonal structures such as spars, ribs, longerons, or bulkheads. For the last couple of decades, unitized structure and composite material based structure have demonstrated great potential to balance competing performance and cost requirements in aircraft design and, in some instances, attain performance beyond traditional capabilities. AFRL is interested in exploring advanced structural technologies that enable lightweight and low cost structure. Research opportunities exist in advanced structural concept design, multifunctional structure, low cost manufacturing, and design for assembly, maintenance, and repair. The topics of research include but are not limited to: (1) Structural optimization using topology optimization; (2) Innovative structural concepts (e.g., morphing / reconfigurable mechanism or structure, bio-inspired structure, tensegrity structures, etc); (3) Multi-functional structures (e.g. antenna integrated structure, battery integrated structure, etc); (4) Design for low-cost manufacturing/assembly; (5) Structure design using advanced prototyping (e.g., continuous fiber composite, automated fiber placement, additive manufacturing, smart tools, etc); (6) Enabling structural materials and actuators (e.g. flexible/corrugated skin structure, meta material structure, smart material structure, novel hybrid compact actuators); and more.
Keywords: Aircraft design, structural design, innovative structural concepts, topology optimization, multi-functional structures, advanced control surfaces, design for low-cost manufacturing.

SF.30.02.B4962: Superconductors, Thermoelectrics, Carbon Nanotubes, and Magnetic Materials for Advanced Power Applications

Haugan, Timothy - (937) 225-7163

The discovery of high-temperature superconductors (HTS), carbon nanotubes, thermoelectrics, and advanced magnetic materials offers many possibilities for their application in energy, power, and thermal applications and systems. However, a basic understanding of these materials, uniquely engineered structures, or the discovery of new materials (for superconductors, thermoelectrics, and magnetic materials) with their associated development is necessary to realize these applications. We are interested in both experimental and theoretical work, and modeling and simulation to accomplish these goals. Also the design and development of power devices is of interest to understand and demonstrate new capabilities. The following discusses each area as well as relevant general capabilities needed. In HTS, current emphasis is placed on the search for new superconductors at higher temperatures or more isotropic in current transport, and preferably operating above liquid hydrogen temperatures. Basic research is performed for the development of wire conductors, with emphasis on magnetic flux pinning enhancement, ac loss understanding and minimization, and stability and quench. Development of advanced superconducting wire is acceptable and can include conductor or cable configurations and coil windings. Thermoelectrics explore properties either at higher temperature for waste heat applications or as a means for cooling through the Peltier effect. Material emphasis is placed on multilayers and other nanostructures, oxides, and carbon nanotubes. Carbon nanotubes and composites are studied with an eventual goal to either achieve long lengths for electrical wiring/data transmission, or for thermal transport and structural support in a variety of electro-thermal environments including cryogenic. Magnetic materials research focuses on developing improved permanent magnets, such as high saturation and nanoparticle composite materials, and on soft magnetic material. Pulsed laser deposition, MOCVD, and MOD are the principal processes for thin-film growth in addition to the different materials for study of superconductors and thermoelectrics. Bulk growth of the magnetic materials and superconductors is of primary interest. CVD (both thermal and microwave) is typically used for growth of the carbon nanotubes.

Eligibility: Open to U.S. citizens

SF.30.02.B4834: Wide Temperature Range Power Semiconductors

Merrett, Neil - 937-952-9181

Research opportunities exist in the areas of power device design, development, and reliability assessment as they relate to wide bandgap power switch and diode performance in harsh environments. In addition to a consideration of carrier transport phenomena over wide temperature operational ranges, current research is focused on the thermo-mechanical aspects of device packaging to minimize CTE-related stresses and enhance reliability while providing the requisite electrical functionality. Novel composite and metallurgical materials are being investigated in module designs which aim to functionally optimize heat transfer efficiency and temperature distributions to minimize the stresses which drive conventional packaging failure modes. FEA modeling and simulation are extensively used to drive component designs which are subsequently validated empirically. In conjunction with this area of research is an interest in developing thermal models of heat transport across small-dimensional layers and interfaces that are not accurately described by Fourier conduction theory. A closely related area of research is in improving our understanding of the fundamental physics and chemistry of device failure in these emerging wide bandgap material systems. Efforts to determine activation energies and correlate device failure data with resident dislocations, inclusions, micropipe, and other defects is an area of high priority. Research interest also exists to develop sensors and optical interrogation techniques that are capable of providing accurate, repeatable, high-resolution response to small changes (<5%) in pressure, temperature, electrical current, voltage, and fluid flow under similar thermal environments.

Eligibility: Open to U.S. citizens

SF.30.02.B4272: Research and Development of Efficient and Novel Thermal Management Approaches for Airborne Vehicles

Roman, Abdeel - (937) 904-6905

Heat acquisition, transport, storage, and rejection represent fundamental limitations for future high-power, high-energy missions and for high-performance aerospace vehicles. Basic and applied heat-transfer and thermodynamic phenomena are examined analytically and experimentally with emphasis on their adaptation to airborne power-systems, electronic component thermal management, and directed energy weapon thermal management. Areas of interest include, but are not limited to single-phase, two-phase, multiphase systems, and high-performance rapid-responding thermodynamic systems; novel working fluid approaches for low and high temperatures (-55 degC to >300 degC for high-performance dielectric materials); nano and micro scale thermophysics; concurrent and countercurrent heat-transfer devices; capillary and other augmented heat-transfer methods for variable gravity applications; novel thermophysical and heat-transfer phenomena characterization; high- and low-temperature heat-transfer fluid-properties verification; unsteady heat transfer in pulsed and transient-phase change processes; analysis and verification of direct and indirect liquid cooling for electronic component temperature control; and the solution of the conjugate problem associated with this configuration for silicon carbide applications.

Eligibility: Open to U.S. citizens

SF.30.02.B0110: Applied Atomic and Molecular Spectroscopy

Adams, Steven - (937) 255-6737

Spectroscopic methods are developed and applied for quantitative measurements in nonequilibrium plasmas and high-temperature reacting flows. Well-defined low to medium pressure discharges using CW and pulsed direct current, low frequency to radio frequency, microwave excitations, and tandem pulsed-microwave excitations are investigated for their application to flow control in hypersonics, plasma enhanced etching, surface modifications, and dielectric breakdown. Experimental and theoretical studies are being conducted to characterize homogeneous and heterogenous processes in plasmas including plasma-surface interactions, plasma assisted ignition, and the creation and influence of self-ordered nanoparticles in plasmas. Power deposition scaling of atmospheric and near atmospheric pressure plasma properties including microplasmas are quantified by Stark spectroscopy, one- and two-photon allowed laser-induced fluorescence, Raman scattering, and photo absorption measurements using tunable visible to near-infrared, narrow line width diode laser sources. Experimental results are supported by theoretical modeling of electron kinetics and heavy particle interactions in nonequilibrium plasmas. A triple stage differentially pumped mass spectrometer is used to study transient discharge phenomena and photocatalytic reactions at medium to high pressure. We are also investigating the flux scaling properties of atmospheric pressure or near atmospheric pressure DBD plasma jet excited by short pulse duration, high reduced electric field dielectric barrier discharges for both vacuum ultraviolet/ultraviolet light source and low-cost surface coating applications.

Eligibility: Open to U.S. citizens

SF.30.02.B0109: Physics of Electric Discharges

Adams, S - (937) 255-6737

Basics atomic, molecular, and optical physics of electrically excited non-equilibrium gases are studied in a number of excited gas configurations including direct current, radio frequency, and microwave discharges, as well as laser excited gases. Research is primarily experimental and includes studies of ionization cross sections and ion-molecule reaction rates, excitation processes, energy transfer processes under non-equilibrium conditions, and gas breakdown mechanisms. Experimental facilities include a high resolution Fourier-transform mass spectrometer, modified for ionization cross section measurements, pulsed inductively coupled plasma source, laser excitation sources, plasma diagnostics including optical emission and absorption spectrometers, microwave interferometer and Langmuir probes. Applications include plasma processing and decontamination, control of plasma characteristics, and laser control of spark ignition.

Eligibility: Open to U.S. citizens

SF.30.01.B6706: Unsteady Aerodynamics and Heat Transfer in Turbines

Clark, J - (937) 255-7152

An accurate accounting of unsteady flow phenomena is critical to the successful design of turbine components. This is especially true for future systems, where it is desirable both to increase engine performance and to reduce operating costs. Phenomena of current interest include vane-blade interactions, unsteady shock boundary-layer interaction, boundary-layer transition, separation control, and unsteady heat transfer and cooling as a result of the passage of turbine blade tips over outer air seals. Research opportunities in the turbine branch of the Turbine Engine Division typically have combined design, analysis, and experimental aspects. A complete design, analysis, and optimization system is in place to create advanced turbine components for validation testing in the laboratory. For example, by capitalizing on advances in transition modeling made at the laboratory, the system was used successfully to define exceptionally high lift low pressure turbine airfoils. High pressure turbine components with low heat load have also been defined and validated and we anticipate that further advances in the state-of-the-art in turbine aerothermodynamics are achievable with these design tools. Therefore, we are particularly interested in analytical work to improve the design system, including improvements in optimization techniques. In addition, a hybrid Reynolds-Averaged Navier Stokes/Large Eddy Simulation code is now being developed for incorporation into the system. It is also possible to access computational resources at the US Air Force Shared Resource Center to support projects. Experimental facilities available for design system validation and other research run the gamut from low-speed wind tunnels suitable for the assessment of fundamental flow physics on flat plates and cylinders in cross-flow, to low- and high-speed linear cascades (with and without heat transfer and/or cooling) and full scale, rotating transonic turbine rigs.

Eligibility: Open to U.S. citizens

SF.30.01.B5438: Improving Structural Dynamic and Material Characteristic Understanding of Turbomachinery Components

Holycross, Casey - 937-656-5530

To continue improving both performance and durability of gas turbine engines, a better understanding of the structural behavior of components is essential. Though structural capability of all engine componentry is assessed with rigor, critical components such as airfoils, disks, and integrally bladed disks (IBDs) are scrutinized more heavily than others. With advanced, sixth-generation engines requiring novel design concepts and non-conventional manufacturing methods to meet performance demands, the framework for structural assessment must be updated to define acceptable sustainment criteria for critical components. This research opportunity aims to address the need for improved structural characterization that will reduce the likelihood of legacy and developmental gas turbine engine components failing, Structural characterization requiring attention is based on vibration suppression, fatigue behavior analysis, and strength assessment.
Computational and experimental research to understand structural behavior of turbomachinery components is being conducted by the Turbine Engine Integrity Branch (RQTI) in the Aerospace Systems Directorate of AFRL. The research areas include mistuning, nonlinear vibration, applied damping prediction, system identification, damage detection, probabilistic analysis, fatigue life and crack growth predictions, additive manufacturing, thermomechanical fatigue, multiphysics lifing, and development of new structural design approaches. Within these areas are several key research topics that require the integration of experimentation and analysis. Ongoing work consists of modal characterization via finite element methods and bench experimentation, standard fatigue and fracture characterization using mechanical testing and physics-based modeling, novel component and material testing development leveraging reduced order modeling (ROM) and surrogate response prediction, and uncertainty quantification in analysis and experimental methods.
To support the aforementioned research, both experimental and computational facilities are available within RQTI. The Turbine Engine Fatigue Facility (TEFF) is a state-of-the-art research facility that performs structural and dynamic experimentation. The TEFF directly supports Air Force legacy fleets, as well as developmental programs through basic research in the areas of material characterization, vibratory assessment, life prediction modeling, and qualification of advanced measurement techniques. Experimental capabilities in the TEFF include scanning laser vibrometry, advanced geometric optical scanner, digital microscopy, triangulation displacement sensor, ping dynamic frequency analysis, large-to-small scale electrodynamic shakers, high-frequency/ultrasonic shakers, high-temperature induction and resistance ovens, single- and multi-axial servo-hydraulic load frames, traveling wave excitation system, and vacuum spin chamber for small IBDs. The Structural Analysis Group (SAG) is the high-performance computational research area leveraging physics-based understandings from finite element methods and computational fluid dynamics. The integrated work conducted by the SAG utilizes finite element software ANSYS, mathematical programming language MATLAB, executable programming languages Python and LabVIEW, computational fluid dynamics software STAR-CCM, mistuning ROM algorithm MAGMA, and digital twin solid model algorithm MORPH.
Turbine engine; Structural dynamics; Additive manufacturing; Fatigue; Mistuning; Damping; Prediction models; Airfoil; Material properties;
Citizenship: Open to U.S. citizens
Level: Open to Regular and Senior applicants

SF.30.01.B5437: Advanced Diagnostics for High-Speed Flows

Carter, Campbell - (937) 255-7203

This research addresses technologies essential to high-speed, air-breathing propulsion, including fuel-air mixing processes in subsonic and supersonic flows and the role of turbulent transport on mixing and combustion in high-speed flows.

Objectives include the following: (1) incorporation of science into preliminary design and advanced development of ram/scramjet combustors; (2) development and application of accurate CFD tools for the design and analysis of ramjet/scramjet combustors; (3) development and application of advanced non-intrusive optical diagnostic techniques for high-speed reacting flows; (4) study of ionized flows on a confined supersonic flow, especially for enhanced combustion; and (5) transition of basic research ideas, concepts, and findings to exploratory development programs.

In particular, three areas of focus are supported: (1) Fuel Control and Fuel Injection, wherein fundamental aspects are studied for gaseous, supercritical, and multiphase fuels; (2) Ignition, Flameholding, and Flame Propagation in Supersonic Flows, wherein fundamental aspects are studied with a view towards improving performance in a high-speed combustor; and (3) Multidisciplinary Laser Measurements for benchmarking modeling and simulation and for elucidating the physics of high-speed flows.

Both laboratory-scale and large-scale (e.g., within a supersonic combusting ramjet engine) experiments are employed. Facilities include extensive high-speed wind tunnels, where conventional and advanced diagnostics can be employed, and a well-equipped optics laboratory, where techniques and ideas can be explored in small-scale flows prior to being employed in the large-scale facilities.

Eligibility: Open to U.S. citizens only

SF.30.01.B0112: Studies of Novel Combustion Concepts for Propulsion Systems

Holley, Adam - 937-255-7487

AFRL`s Combustion Branch plans, develops, and transitions basic research and applied technology development programs for military air-breathing engines. We do this by executing in-house and contracted programs that enhance the capability of turbo-propulsion systems through design, analysis, development, and test of advanced combustion systems. Additionally, the branch explores novel propulsion concepts critical to meeting future Air Force requirements. Some of these novel concepts include pulsed-detonation engines, inter-turbine burners, and trapped vortex combustors. The branch has in-house activities associated with these concepts.
The branch evaluates and enhances component capabilities through the understanding and innovative use of chemistry, aerodynamics, heat transfer, materials, diagnostics, computational fluid dynamics, and design tools. Areas of fundamental research include fuel injection, fuel-air mixing, fuel atomization, chemical kinetics, flame stability, supercritical fuel injection, flame dynamics and ignition phenomena. A growing focus area is the understanding the chemistry and combustion characteristics of alternative fuels for new propulsion systems. Well-equipped laboratory laboratories and computational resources are available to carry out the research activities. The laboratories can operate at sub-atmospheric to 40 atmosphere conditions, and include a host of intrusive and non-intrusive diagnostic capabilities.

SF.30.01.B0104: Aero and Thermodynamics of Rotating Machinery

Sondergaard, R - (937) 255-7190

An improved understanding of internal flows and heat transfer under non-steady conditions is necessary for the continued advancement of turbine engine performance. Shortcomings in the ability to accurately predict aerodynamics and heat transfer of cooled and uncooled components in the hot section significantly impacts the design and development cost of new engines and component performance and durability. Improvements in specific fuel consumption are largely related to the ability to increase turbine inlet temperature and cycle pressure ratio, which are limited by the ability to model these flows. Important research areas include internal and external cooling of vanes, turbine blades, shrouds, platforms, broach slots, and disk cavities. Also important is the understanding and control of the aerodynamics and aerodynamic losses associated with these components. Nearly all of these flows are three dimensional and unsteady, and must be characterized over a large range of operating conditions, including low Reynolds number conditions at which flow separations become major contributors to aerodynamic losses. Strong pressure gradients, density gradients, curvature, rotation, and compressive effects are present in many of these flows. Non-steady shocks and shock boundary layer interactions can also be important.

Of interest are experimental and computational investigations studying methods of increasing film cooling effectiveness, techniques for selectively increasing or decreasing heat transfer coefficients, methods of flow control to increase blade loading, reduce passage, hub and tip losses, and techniques for controlling aeroelastic effects and damping. Characterization of aerodynamic, thermal, and structural effects requires non-steady two- and three-dimensional computational schemes and experimental techniques. The spatial and temporal resolutions need to approach wall flow scales in order to provide the accurate time-resolved blade vane interaction effects, as well as resolve loss mechanisms and heat transfer associated with other non-steady secondary flow phenomena that are present. Specific computational interests are three-dimensional non-steady, multidisciplinary approaches that are capable of optimizing aerodynamic, thermal, and structural designs.

Eligibility: Open to U.S. citizens

SF.30.01.B0103: Engine Mechanical Systems Component Modeling, Simulation and Validation

Nicholson, Brian - 937-255-7567

This research focuses on developing and validating mechanical system component technologies (bearings, gears, and lubricants) and associated modeling and simulation (M&S) tools for advanced aircraft turbine engines. The ability to accurately model and design engine mechanical components, namely mainshaft bearings and gears, using physics-based, first-principles approaches has been a long standing technical challenge due to the complex, multi-physics phenomenon and processes involved. Hence, these components are typically overdesigned and optimum design life and performance targets are seldom achieved.

Specific computational interests include models that can accurately capture three-dimensional surface and sub-surface interactions for predicting component life, heat generation, and overall performance. The goal is to integrate surface tribological effects, including but not limited to lubricant traction, full elastohydrodynamic lubrication, boundary and mixed-mode lubrication tribo-chemistry effects, and surface roughness and topographical features with sub-surface continuum solid mechanics including sub-surface state of stress, residual stress fields and material microstructural evolution. The intent is to develop high-fidelity mechanical component life, thermal and dynamic prediction tools for optimum and cost-effective engine designs.

World class facilities equipped with unique test equipment and instrumentation are available for experimental model validation and development. Access to commercial and in-house developed codes and computing resources at the AFRL DoD Super Computing Resource Center is available.

U.S. citizenship is required.

SF.30.01.B0102: Application of Analytical Data Tools for Investigation of Chemical Data to Performance Properties for Aviation Fuel

Wrzesinski, Paul - 937-255-4867

The development of analytical data tools for the study of large datasets has greatly grown in prevalence in the last several years, and been applied to many fields of study. Aviation fuel remains an area of high interest and rich for study using these tools. Aviation fuel has a broad data profile that captures fundamental chemical composition, specification data, fit-for-purpose properties, and other performance metrics. This provides a data rich environment for leveraging data tools to look at the relationships between chemical composition and its influence on various physical and performance properties. Research in this area will focus on the use of compositional data, i.e., bulk hydrocarbon profile, traces species present, etc., for a wide array of fuels with varying physical and performance properties. The goal will be to elucidate new relationships and correlations between the chemical data and the physical and performance properties. This research also examines how compositional information can be incorporated into chemical kinetics and fluid dynamics modelling efforts. Current fuels, whether derived from traditional crude or other sources, such as oil shale and tar sands, are included in this research, along with alternative fuels (those derived from non-petroleum sources). Cleared for Public Release: Case Number 88ABW-2020-2355 Eligibility: Open to U.S. citizens

SF.30.01.B0101: Combustion Research for Gas Turbine Engine Applications

Caswell, Andrew - 937-255-7098

Significant challenges remain for the design and optimization of next generation gas turbine engine combustion systems. Fundamental research is solicited to address key questions pertaining to a broad range of applications such as gas turbine main combustors, augmentors, ramjets, and detonation combustors.
In particular, this research will address the physics and chemistry of fundamental processes in gas turbine combustion systems through the study of isolated and interacting droplets, sprays, premixed and non-premixed flames, swirl-stabilized flames, bluff-body flames, and cavity-stabilized flames. Continuing work requires experimental and theoretical approaches related to the following: (1) turbulent transport, mixing, entrainment, evaporation, droplet drag, drop-spacing effects, atomization, finite-rate chemistry, flame stability, ignition, and blow-out; (2) development and application of laser and optical based diagnostic techniques to support combustion and spray experiments, and (3) studies using state-of-the-art time-dependent reacting flow simulations.
The research is intended to align with the goals and objectives of the work being conducted at the Air Force Research Laboratory. Numerous well-equipped laboratories containing small- and large-scale combustion experimental arrangements and advanced laser diagnostic equipment designed for two-dimensional imaging, laser absorption spectroscopy, coherent anti-Stokes Raman spectroscopy; laser Doppler anemometry; phase Doppler particle sizing; laser-induced florescence techniques; and femto/picosecond chemistry studies exists. Access to various combustion CFD codes and the DOD ASC Major Shared Resource Center is available for theoretical studies.
Eligibility: Open to U.S. citizens only Keywords: Combustion; Laser Diagnostics; Gas Turbine Engines; Combustors; Augmentors; Afterburners; Propulsion; Power generation; Combustion experiments; Combustion modeling; Computational fluid dynamics (CFD); Large eddy simulations (LES); Detonations; Rotating detonation engines (RDE)

SF.30.01.B0100: CFD for High-Speed Propulsion

Hagenmaier, Mark - 937-255-7325

Development of high-speed air-breathing propulsion is contingent upon an improved understanding of the fundamental processes that govern engine operability and performance. Computational fluid dynamics, in conjunction with experimental fluid dynamics, improves that understanding. This topic welcomes research on ramjet/scramjet and mixed-cycle propulsion components applicable to supersonic and hypersonic flight regimes. This includes interactions between the gas flow, liquid fuel flow and the structural components. Research is desired in the following areas:

1. Improvements to relevant modeling approaches for this flow regime, including numerical approaches and physical modeling.

2. Applications of CFD to enhance compression system performance and operability

3. Applications of CFD to enhance combustion system performance and operability, including fuel injection, atomization, droplet transport, evaporation, and flame stabilization

4. Application of uncertainty quantification, reduced order modeling, and optimization approaches for CFD.

Eligibility: Open to U.S. citizens

SF.05.14.B0848: High Capacity, Advanced Battery Development

Fellner, Joseph - 937-255-2832

Rechargeable lithium polymer batteries are of interest because of the very high-energy densities achievable relative to that of current generation batteries such as nickel-hydrogen. A key problem associated with the development of this battery has been the poor performance of the polymer electrolyte at ambient and subambient temperatures. Recent developments within our laboratory have demonstrated that a solid-state lithium ion conducting electrolyte (lithium ion conducting channel) can function over a broad temperature range from + 100 C to -50 C with very high specific conductivities on the order of 10 to 100 mS/cm. This electrolyte is particularly attractive since the transference number for lithium is one. The electrolyte was designed by computational chemistry with this feature as the anion matrix provides a constant negative electrostatic potential throughout the molecular system. This characteristic is important for operating over a broad temperature range since lithium ion transport no longer depends on polymer segmental motion but on the electric field gradient created by the potential difference of the electrodes within the electrochemical cell. Our goals are to simulate the electric field gradient using computational chemistry and applying it to the lithium ion conducting channel molecular system in order to correlate molecular structure with ionic conductivity. In addition, we intend to investigate the electrolyte/electrode interface through computational chemistry. We conduct research on ramjet/scramjet and mixed-cycle propulsion.

SF.05.14.B0847: High Performance Electricmechancal Actuation System Thermal Management

Leland, Q - (937) 255-3060

This topic focuses on research and development of aircraft High-Performance Electric Actuation System (HPEAS) technologies. Specific areas include thermal management (TM) of electromechanical actuators (EMA) and motor control electronics; jam free or fault tolerance designs; innovative peak and regenerative power management; and prognostics and health management technologies. For TM, any solutions, liquid or air or other heat transport medium, active or passive, should be integrated with the actuation system as well as with the aircraft electric power system and air vehicle. For example, when implementing an air cooling solution, its heat sink requirement and electric power input should be in agreement with the aircraft’s flight envelope. The ultimate goal of this topic is an optimized HPEAS design fully integrated with thermal management solution and electric power system in an aircraft environment. HPEAS offers considerable advantages over conventional hydraulic actuation system for air vehicles. Three technical challenges have to be addressed for a successful transition of EMA to aircraft flight critical control actuation: thermal management, fault tolerance, and peak and regenerative power management. EMA and its electronics operate under harsh environments, especially those for primary flight control and propulsion system controls for military fighter aircraft. Its environmental temperature ranges from -40o C to 125o C, its heat loads are highly transient and localized, making thermal management one of the critical challenges for HPEAS. The dynamic power level, both peak power draw and regenerative power, also poses a great challenge for the aircraft electric power system. Reliability or fault/jam tolerance has to be proven as good as conventional hydraulic actuation before its acceptance to primary flight control. Keywords: Thermal management; Electromechanical actuator; HPEAS; flight control actuator; EMA; Power electronics cooling; Aircraft actuation; Regenerative power *Eligibility: Open to U.S. citizens only.

SF.05.14.B0847: Electromechanical Actuation System for Aircraft Flight Control

Leland, Q. - (937) 255-3060

This topic focuses on research and development of aircraft High-Performance Electric Actuation System (HPEAS) technologies. Specific areas include thermal management (TM) of electromechanical actuators (EMA) and motor control electronics; jam free or fault tolerance designs; innovative peak and regenerative power management; and prognostics and health management technologies. For TM, any solutions, liquid or air or other heat transport medium, active or passive, should be integrated with the actuation system as well as with the aircraft electric power system and air vehicle. For example, when implementing an air cooling solution, its heat sink requirement and electric power input should be in agreement with the aircraft’s flight envelope. The ultimate goal of this topic is an optimized HPEAS design fully integrated with thermal management solution and electric power system in an aircraft environment. HPEAS offers considerable advantages over conventional hydraulic actuation system for air vehicles. Three technical challenges have to be addressed for a successful transition of EMA to aircraft flight critical control actuation: thermal management, fault tolerance, and peak and regenerative power management. EMA and its electronics operate under harsh environments, especially those for primary flight control and propulsion system controls for military fighter aircraft. Its environmental temperature ranges from -40o C to 125o C, its heat loads are highly transient and localized, making thermal management one of the critical challenges for HPEAS. The dynamic power level, both peak power draw and regenerative power, also poses a great challenge for the aircraft electric power system. Reliability or fault/jam tolerance has to be proven as good as conventional hydraulic actuation before its acceptance to primary flight control. Keywords: Thermal management; Electromechanical actuator; HPEAS; flight control actuator; EMA; Power electronics cooling; Aircraft actuation; Regenerative power *Eligibility: Open to U.S. citizens only.

SF.05.13.B1914: Trajectory Planning for Unmanned Aerial Vehicle Systems

Grymin, D - (937) 713-7235

This research area is focused on the rapid generation of feasible trajectories for autonomous aircraft systems. General scenarios of interest involve position and orientation constraints on the vehicle, disturbance/environmental effects, and aircraft performance constraints. Mission planning may also be subject to various objective costs, and the tradeoff between optimality and computation time is a further area of concern. Examples of scenarios include, but are not limited to: (1) single vehicle planning between multiple tasks; (2) multiple vehicle planning subject to collision avoidance constraints; (3) multiple vehicle planning between tasks; (4) single and multiple vehicle planning incorporating aircraft performance constraints; (5) single vehicle planning in dynamic environments. We are interested in the development of new algorithms and approaches as well as novel applications and implementations of existing methods.

SF.05.13.B1221: Multiscale, Multiphysics and Multifidelity Modeling of Aircraft Power and Thermal Systems

Patnaik, Soumya - 9376565452

Cross-domain, advanced physics based modeling and simulation tools have been identified by the Air Force as game changers that can significantly reduce development and deployment cycle time for acquisition. Our research focuses on development of computational methods, tools and models for design and performance-analysis of aircraft power and thermal (P&T) management systems. The performance analysis of these systems is applied towards exploring the multi-dimensional P&T trade space and developing technology impact forecast. Aircraft P&T systems demand both static and dynamic response and include technologies that represent physical phenomena across a wide range of spatial and/or temporal scales involving multi-physics coupled interactions. Our M&S effort therefore includes multiscale, multiphysics and multifidelity modeling and includes development of computational methods, numerical formulations and software with an integrated and unifying modeling framework. To support this, we are also developing an integrated P&T modeling workspace. Summer research opportunities include but are not limited to: System of systems studies, P&T modeling toolset development; Dynamic modeling of P&T systems; High fidelity thermodynamic analysis of aircraft P&T systems; Molecular and multiscale modeling of heat transfer and thermal energy storage; Molecular and stochastic simulation methods of nanoscale transport phenomenon; Reduced order modeling of P&T systems; Co-simulation of dynamic systems; Model verification and error estimation methods. Access to several commercial and in-house developed codes and computing resources at the AFRL DoD. Super Computing Resource Center is available.

SF.05.08.B6657: Analytic Sensitivities and Machine Learning applied to Uncertainty Quantification for Multidisciplinary Systems Analysis & Design Optimization

Forster, Edwin - (937)713-7148

Uncertainty Quantification (UQ) is historically performed late in the design cycle, when mitigation of deficiencies is costly or may result in a penalty to performance or capability. These late defects and faults may be critical due to unanticipated interdisciplinary couplings or due to the uncertain nature (both aleatoric and epistemic) of anticipated interdisciplinary quantities of interest. Types of uncertainty may include, but are not limited to: a) parameter uncertainties, such as model or design parameters, geometric or material variables, and parameters associated with environment and process control; b) model uncertainties, such as from physics-based models from simple to complex, empirical models based on experiments, couplings/interfaces between disciplines, and model boundary conditions; c) data uncertainties, including noise, measurement errors, and missing data; d) requirements or usage uncertainty, including uncertainty in constraints; and, e) uncertainties arising from simulation, including discretization errors, round-off errors, and algorithmic errors. A scalable and holistic UQ framework that enables the simultaneous inclusion of multi-physics and multi-fidelity models as well as experimental data at varying levels of trust is necessary to address UQ in Multidisciplinary Analysis and Design Optimization (MADO). Such a framework must leverage existing methods and develop new approaches to address increased computational expense and accuracy requirements of UQ within a design environment. Research opportunities exist in the general area of UQ, and in particular sensitivity analysis and machine learning applied to non-deterministic approaches. Topics of interest include (1) methods for developing analytic sensitivities of aerospace system robustness and reliability to design parameters; (2) methods for developing analytic sensitivities of uncertain quantities of interest with respect to distributed stochastic and statistical parameters; (3) machine learning methods applied to multi-physics/multi-fidelity models for prediction of uncertain quantities of interest; (4) machine learning methods applied to data fusion from models and experiments with varying levels of trust ; (5) application of Design of Experiment techniques for modeling and simulation of failures; (6) efficient and accurate methods for predicting rare events (in the tails of probability distributions, on the order of 1e-7 to 1e-9); and, (7) the development of methods which quantify the level of confidence or credibility of a design accounting for uncertainties throughout the design process.

SF.05.00.B8577: Adaptive Structures Applications to Aircraft

Reich, Gregory - 937-713-7138

Adaptivity of aircraft structures and systems can lead to improved performance across the flight envelope at off-design points for a given system. Adaptivity spans the entire range of vehicle size and speed scales, from super- and hyper-sonic systems down to SUAS, and can take many forms – from mechanized wing structures to adaptive devices that locally impact flow. Adaptive systems can utilize conventional materials and actuators, but most find improved chances of success with incorporation of adaptive materials due to the ability to create multifunctionality in the structure. Our research focuses on conception, design, and analysis of adaptive structures, demonstrating how those systems may be used, and quantifying the performance improvement possible. Topology optimization and other techniques are applied to numerical models in a multidisciplinary analysis environment to create new concepts and designs. Our work is focused in several areas: the integration and distribution of actuation into a structure in order to effectively move the structure using minimum energy; the design of novel structural layouts and mechanization concepts using topology optimization schemes tied to linear and nonlinear coupled multidisciplinary analysis; the development of secondary structures, sensors, or accompanying concepts that enhance the adaptivity benefit; and the application of adaptive technologies to unique aircraft systems. Keywords: reconfiguration/morphing/adaptivity, adaptive structures, topology optimization, multidisciplinary design and optimization, multifunctional structures

SF.05.00.B6113: Residual Stress Engineering Technologies for Aircraft Structural Components

Spradlin, Thomas - (937) 656-8813

Residual stresses – whether introduced via the manufacturing process or via surface treatment (e.g., laser peening or cold working) – alter the fatigue and fracture response of metallic airframe components. In many cases these stresses can be exploited to extend the life of the component with attendant benefits of increased safety, reduced operational costs, and improved performance. However, for full exploitation of these technologies for airframe life extension, in particular, the explicit consideration of residual stresses in determining non-destructive inspection intervals, validated design and analysis tools are required that can accurately and efficiently determine the effects of residual stresses on the design life of replacement and/or existing components. Validated tools will enable more cost effective developments of residual stress solution options by reducing the amount of experimental iteration required to field new applications. Further, such methods will allow designers to optimize residual stress treatments for specific lifing objectives, as well as study the effects of error and uncertainty.
To meet these objectives, research opportunities exist in the area of design, experimental validation, and life prediction for residual stress-enhanced aircraft structural components. Residual stress processes of interest include but are not limited to manufacturing processes such as forging, machining, and welding, as well as surface treatments such as laser peening, water jet peening, and UNSM (ultrasonic nanocrystal surface modification). Lifing approaches should include the prediction of crack growth rates and fracture paths compatible within a damage tolerance framework. Advances in validation techniques can include both destructive and nondestructive methods for quality assurance, stress evaluation, and crack growth tracking.
Specific topics include:
(1) Development of validated and efficient analysis techniques and design tools for predicting the fatigue characteristics of residual stress-enhanced airframe components under spectrum loading, including realistic initial conditions such as prior fatigue exposure, shot peening, and/or manufacturing-induced residual stresses.
(2) Development of stochastic analysis techniques for quantifying the effects of input uncertainties, such as processing parameters or material response, on the predicted fatigue response of a residual stress-treated component.
(3) Development of validated damage tolerance analysis methods for aircraft structural components to study the effects of deep residual stresses on fatigue crack propagation. Fatigue life prediction models should account for residual stress redistribution, work hardening, and/or surface deformation.

SF.05.00.B6110: Design, Measurement, Modeling, Analysis, and Control for Optimal Weapon Integration

Stanek, M - (937) 656-8767

The addition of turrets, pods, external stores and tanks, and weapons bays to advanced air and near-space military flight platforms are required to turn these flight assets into practical weapon systems. Unfortunately, these additional features can compromise the overall weapon system performance, due to undesirable effects on unsteady aerodynamic loads, turbulence properties, heat transfer rates, optical signal transmission characteristics, and other factors. Advanced diagnostic techniques, computational analysis, flow control, and advanced modeling are all tools which need to be developed and aggressively applied to integrate advanced weapon concepts on future platforms.

The two classes of weapon integration which are currently of most interest are weapons bays and optical apertures (for directed energy). Basic research opportunities include, but are not limited to the following areas: (1) design, analysis, and modeling of flow control devices to improve baseline integration characteristics; (2) optimization of the combination of aerodynamic shaping and flow control for best performance of the integration; (3) improvements to boundary conditions, turbulence models, physical effects models, and other specific computational aspects to enhance accuracy, fidelity, speed, and usefulness of advanced simulations; (4) the study of dynamic control techniques timed to the release of a store, to enhance trajectory properties; (5) modification of stability properties, turbulence properties, and separation characteristics of shear layers associated with cavities, turrets, or other integrations of interest; (6) development of models for prediction or scaling of flow control devices, and (7) development / use of innovative diagnostic techniques to allow for visual study as well as quantitative description of integration properties with and without flow control. Research could involve analytical modeling, computational simulation, design, experimental simulation, software development, or some combination of all the above.

SF.05.00.B5742: Enabling Robust and Durable Aerospace Structures for Combined, Extreme Environments

Eason, Thomas - 937-656-8802

The objective of this effort is to develop and demonstrate procedures for analyzing, designing, and forecasting the life of aerospace structures that are used in extreme, combined thermo-mechanical-acoustic environments. The emphasis is on understanding the interactions between the different phenomena and properly accounting for the interactions to ensure robustness and durability for reusable, high-speed vehicle structural components.

U.S. citizenship is required for those wishing to co-locate at WPAFB during the summer.

SF.05.00.B5740: Computation of Supersonic and Hypersonic Flow Phenomena and their Control

Bisek, Nicholas - 937-713-7101

Improved supersonic flight and space-access capability with air-breathing hypersonic trajectories are key elements of many future technology development programs because of their profound impact on commercial and military activities. Significant basic research challenges remain to be overcome in these areas, ranging from developing theories of transition and turbulence to predicting and managing the aerothermal and propulsion environment and determining the impact of non-continuum effects, both at global time-mean scales and local time-accurate phenomena. Given the challenges of reproducing flight conditions in ground-test facilities, and limitations and risks with flight tests, simulations have an integral role to minimize risk to future flight programs.

High-fidelity computations of high-speed flows are challenging because of the fundamentally multidisciplinary and three-dimensional environment. In addition to viscous fluid dynamics, it is often essential to consider transitional or turbulence and thermo-chemical non-equilibrium effects such as vibrational excitation, dissociation, ionization and recombination. Reusable long-range hypersonic flight systems will also require breakthroughs in the understanding and implementation of revolutionary concepts such as plasma-based flow control or morphing surfaces likely manufactured from advanced materials that leverage anisotropic properties to achieve a responsive product. Numerical formulations must therefore be extended to include variants of the Maxwell equations and sophisticated plasma models for the gas-phase and a first-principles treatment of necessary meta-species associated with gas-surface interactions. The combined phenomena yield a large, stiff set of non-linear governing equations, which must be resolved with fine spatio-temporal discretizations. It is essential therefore to develop highly accurate physical models, and to couple them to advanced, robust numerical methods which can efficiently exploit massively parallel modern computational systems. In addition, benchmark solutions can be used to inform, refine, and validate lower-cost phenomenological models that are more amenable to the commercial sector.

Broad research opportunities exist to (1) enhance high-fidelity computational techniques, whether particle-based, continuum-based, or coupled; (2) utilize computational tools to investigate a variety of physical phenomena, including direct numerical simulations of high speed transition and turbulent flows, and shock/boundary layer interactions;(3) develop, implement and validate aero-thermo-chemical models for state-to-state kinetics; (4) explore drag reduction and thermal protection technologies; (5) utilize computational techniques, including machine learning, in the detailed analysis of relevant flow physics.

Eligibility: Open to U.S. citizens wishing to co-locate to WPAFB for the summer.

SF.05.00.B5739: Computational Fluid Dynamics Research in Numerical Simulation of Turbulence Flows

Rizzetta, D - (937) 713-7104

Research opportunities exist to examine complex flow situations, employing direct numerical simulation(DNS) and large-eddy simulation(LES) in order to represent turbulent structures. Problems are considered which have both fundamental scientific and practical significance. Current efforts focus on developing high-order numerical procedures employing implicit LES techniques, as well as solutions of the Favre-filtered Navier-Stokes equations. For the later, improved subgrid-stress modeling is sought. Recent applications have been devoted to plasma-based flow control for low-Reynolds number airfoils and wings. Previous efforts have included simulation of supersonic compression-ramp flows with shock waves, acoustic suppression of aircraft weapons bay cavities using flow control, investigation of transitional flow past low-pressure turbine cascades, and roughness generated transition. We also have interest in applying the Reynolds-averaged Navier-Stokes(RANS) approach for practical computations. For this purpose, two-equation models and Reynolds stress formulations have been considered. Hybrid turbulence models for unsteady RANS applications and detached-eddy simulation(DES) are also being examined.

SF.05.00.B4943: Computational Aeroelasticity and Fluid/Structure Interaction

Barnes, Caleb - (937) 713-7103

The need to expand flight envelopes and mission requirements for existing aircraft, and the design of new highly flexible and maneuverable aircraft has driven interest in developing nonlinear aeroelastic analysis capabilities. Research opportunities focus on the simulation of complex fluid/structure interactions. Emphasis is placed on coupling high fidelity, nonlinear, fluid dynamics solvers with nonlinear structural mechanics. These simulation techniques will be used to investigate the response of flexible aircraft structural components to unsteady aerodynamic loadings and maneuvers. Research topics include (1) the development of algorithms to solve the nonlinear structural dynamics equations coupled with fluid dynamics equations; (2) applying computational tools for detailed investigations of fluid/structure interaction problems, including buffet phenomena, flutter, limit cycle oscillations, unsteady maneuvers and gust interactions; (3) novel techniques for grid deformation and fluid/structure interface treatment; and (4) development of multidisciplinary fluid/structure algorithms appropriate for a massively parallel computing environment.

SF.05.00.B4617: Adaptive Computational Methods for Capturing Multi-Physics Interactions

Beran, P - (937) 713-7217

Aerospace systems are growing increasingly complex and are exhibiting a wider range of coupled physics phenomena. As a result, computational analysis of these systems is becoming more complicated, especially in an effort to capture important coupled physics earlier in the design process for the purpose of developing higher performance systems at lower cost. Several challenges exist, but many relate to the problem of integrating and orchestrating models of different levels of fidelity across a wide of physical phenomena while providing useful sensitivity analysis information and meeting accuracy requirements. Research opportunities include, but are not limited to, the following topics:
(1) Development of quantitative, goal-oriented methods to adapt mesh, time step, numerical order, level of physical coupling, and model fidelity for individual analyses to lower computational subject to constraints on error estimates; applicable to steady, time-periodic, and transient phenomena, especially those involving nonlinear interactions.
(2) High-order finite elements methods for solids and fluids featuring rich levels of adaptation with potential for hybrid approaches for multidisciplinary problems.
(3) Adjoint-based approaches for efficient adaptations and sensitivities, particularly for coupled-physics problems.
(4) Computer science approaches to integrating disciplines, facilitating on-the-fly adaptations, and parametrically enriching models, with emphasis on the automated exploration of large design spaces.
(5) Study of critical phenomena involving exchange of static and dynamic stability, and adaptation procedures seeking to minimize errors associated with these features.
(6) Machine learning algorithms and statistical approaches for making decisions about model selection, including the development of surrogate models enriched by sensitivities and informed by a number of different information sources.
(7) Model reduction strategies for reducing the reliance on high-fidelity models as another form of goal-oriented adaptation.
(8) Error estimation and analysis verification for large aggregations of models of arbitrary complexity.
(9) Applications to a wide range of coupled physics phenomena including, but not limited to, disciplines of incompressible and compressible aerodynamics, rigid-body and structural dynamics (with material nonlinearities), heat transfer including radiation, and acoustics. Applications of interest, whether system or component level, should demonstrate how physics drive the design and can be more effectively captured with an adaptive computational process.

SF.05.00.B4615: Hypersonic Boundary Layer Transition and Control

Borg, Matthew - 937-713-6697

The laminar-to-turbulent transition of boundary layers has a much greater impact on the performance and survivability of expendable and reusable hypersonic vehicles than it does on low-speed vehicles. Accurate prediction of the location and mechanisms that lead to transition is difficult because of the sensitivity of transition to initial conditions. Ground testing has been and continues to be a necessary and valuable tool; however, boundary-layer transition is one of the most difficult fluid dynamic phenomena to replicate experimentally. Although computational tools continue to improve and can offer significant insight into the physics of transition, their use is generally limited to specialists and requires significant computational resources. As these disciplines provide deeper insight into transition, the ability to influence/control transition increases. At present, such control is largely limited to specific canonical geometries and conditions.

Basic research opportunities exist in the measurement, prediction, and control of hypersonic boundary-layer transition. Areas of interest include
(1) measurements of hypersonic boundary-layer instabilities and transition
(2) assessing the influence of changes in surface parameters on transition (e.g. temperature profile/gradient, roughness, structural deformation, etc.)
(3) the development, simulation, and ground test of mechanisms to influence/control transition, and
(4) the development and application of computational tools (e.g. stability analyses, reduced-order models, etc.).

Eligibility: Open to U.S. citizens

SF.05.00.B4614: Active Flow Control Modeling and Development

Tilmann, C - (937) 656-8782

Recent developments in small, powerful, and efficient flow control devices have made the application of active flow control systems on future aircraft a viable alternative. Modern flow control effectors and techniques show promise for localized adaptive control of boundary layer separation, laminar to turbulent transition, shear layer turbulence, and secondary flow features. They may also be used to create ‘virtual’ aerodynamic surfaces that can be tailored for changing operating conditions, or to provide flight control. To effectively use these devices in a system requires a multidisciplinary approach that includes further research in sensors, fluids, and adaptive control technologies. We must first acquire knowledge of the base flow to be modified, and determine which flow effectors can most efficiently modify it. We must also determine what flow properties can be sensed in a practical way, and how this information can be used to indicate the state of the flowfield. Then controllers to interpret sensor information, and direct the flow control effectors, can be developed.

Areas of interest include (1) new flow control methods and actuator devices with expanded frequency range, greater amplitude, and improved adaptability; (2) control systems that optimize performance in specific applications; (3) numerical simulation and experimental validation of devices to enhance understanding of the relevant flow physics; (4) integration of existing devices into air vehicle systems; (5) laminar to turbulent transition modeling, prediction, & control; (6) flow control enabled flight control; (7) aero/structure/controls interactions; and (8) development of rapid flow control modeling methods that allow designers to utilize the technologies in design trade studies. Research could involve developing new flow control methodologies, data base development, computational modeling, analytical modeling, and/or software integration.

SF.05.00.B3817: Unmanned and Micro Air Vehicle Guidance, Control and Dynamics

Grymin, David - 937-713-7235

We are committed to the aggressive development and transition of advanced air vehicle control technology to industry and the war fighter to improve total weapon system lethality, survivability, agility, performance, and affordability. Our long-term objective is to develop adaptive and autonomous control theories for the advancement of future Air Force flight vehicles.

Our current research focuses on autonomous and cooperative control of multiple unmanned air vehicles, flight control of flexible wing small UAVs, guidance and control of air-breathing hypersonic vehicles, and verification and validation of flight critical software. Specific research areas include (1) multi-objective optimization for cooperative mission planning involving heterogeneous unmanned vehicles interacting with one or more human operators; (2) cooperative ISR (intelligence, surveillance, and reconnaissance) techniques for multiple vehicles to locate, identify, and track dynamic targets; (3) cooperative strategies for multiple, heterogeneous unmanned air vehicles performing coupled tasks, including the effects of realistic network communication systems such as network latency and delays that result in different target state information on different parts of the distributed decision and control system; (4) autonomous and intelligent control algorithm development, including algorithms with the ability to learn improved responses to a dynamic environment; (5) control oriented modeling of flexible wing small UAVs; (6) control law development for small UAVs that use unsteady aerodynamic and mass property based control effectors; (7) experimental testing and validation of control laws for flexible wing small UAVs; (8) control law and trajectory generation for ground operation of small UAVs while perched, recharging, or operating as a ground based surveillance platform; (9) development of guidance and control laws for air-breathing hypersonic vehicles that provide optimum maneuvering performance while accommodating engine operability and aerodynamic heating constraints; and (10) flight control algorithms for hypersonic vehicles that prevent departure from controlled flight during inlet un-start. Our goal is to develop and validate control algorithms through real-time, nonlinear simulations and experiments, and transition technology to benefit the war fighter.

SF.05.00.B2314: Development of Translaminar Reinforcement Techniques for Bonded Composite Joints

Ranatunga, Vipul - (937) 656-8809

Delamination of laminated composites is one of the main causes of damage experienced in composite structures. Various translaminar reinforcement techniques such as stitching, pinning, tufting, weaving and braiding are commonly employed to improve the delamination resistance and provide a fail-safe bonded or co-cured structure. In order to design damage tolerant composite structural joints, it is necessary to have an in-depth understanding of the delamination growth under various loading conditions. Due to the complexity of loading conditions that exists under service conditions, the delamination growth is commonly studied under the idealized modes such as Mode I, Mode II, Mode III, and well defined combinations of these modes. Research opportunities exist in the area of experimental study and numerical modeling of delamination with translaminar reinforced composites. Proposals are solicited for the development of (1) test procedures to estimate the apparent fracture toughness of translaminar reinforced composites, (2) numerical modeling techniques to simulate delamination in translaminar reinforced composites under static and high-rate dynamic loading conditions.
Previous studies have successfully demonstrated the use of carbon fiber pins or stitches to improve the delamination resistance of laminated composites. Proposed study may include other types of reinforcements applicable to composite aircraft structures.
Keywords: Bonded Joints, Translaminar Reinforcements, Composite Delamination, Finite Element Modeling, Multiscale Modeling.

SF.05.00.B0129: High-Fidelity Multidisciplinary Computational Fluid Dynamics

Garmann, Daniel - 937-713-7084

We conduct basic and applied research in multi-disciplinary high-fidelity computational fluid dynamics, a technology that is critical to the effective development of future Air Force systems. Mutually beneficial collaborations are sought in a broad range of research activities with the main objectives of advancing the state of the art, and complementing and/or expanding in-house capabilities. Opportunities for focused-research include (but are not limited to) the following topics:

(1) Development of high-order computational approaches, including structured and unstructured high-order spatial schemes, high-order implicit time-discretization methods, improved boundary treatments, as well as procedures for accurate solution of aero-acoustics and flows containing both fine-scale and sharp features (e.g. compressible turbulence).

(2) Simulation and improved understanding of vortex flows relevant to maneuvering combat unmanned air vehicles (UCAV) and small unmanned air vehicles (UAV) with emphasis on transition effects, dynamic stall and leading-edge vortex formation and breakdown, wake structure, and unsteady loads (e.g. gust).

(3) Direct (DNS) and Large-Eddy simulation (LES) of transitional and turbulent compressible flows, including improved sub-grid-stress models, inflow conditions for LES, and hybrid RANS/LES approaches extendable to complex configurations.

(4) High-fidelity simulation of active flow control of external and internal transitional, separated and vortical flows employing both traditional and novel techniques (e.g. synthetic jet and plasma-based actuators).

(5) Development of a high-fidelity computational framework for the analysis of aero-optical aberration in the near-field encountered in tactical laser weapon systems. Assessment of the role of aberrating flow structures on overall optical distortion pattern for relevant canonical flows. Investigation of flow control strategies to either regularize or break up large-scale coherent turbulent structures in order to mitigate overall aberration and enable/guide adaptive optic techniques.

SF.05.00.B0123: Mathematical Optimization in Multidisciplinary Design

Kolonay, Raymond - 937 713 7126

The basic objective of multidisciplinary design is to integrate the various disciplines that constitute the environment of an aerospace vehicle. The goal of modern design is to optimize the total system rather than the individual components, permitting the conflicting requirements of the subsystems to be handled much more effectively in getting optimal solutions. Aerospace Vehicle design is a large optimization problem consisting of libraries of variables, constraints, and performance functions. By expanding and contracting these libraries, we can explore the inherent coupling between subsystems and the disciplines and their impact on system level performance. Topics of interest include (1) simultaneous design with multiple constraints; (2) structural requirements derived from strength, stiffness, and frequency considerations; (3) static and dynamic aeroelastic requirements; (4) requirements from acoustic and thermal environments; (5) linear and nonlinear aerodynamic interactions with the structure and control system; (6) tailoring of composites and other new materials; (7) shape and topology optimization; (8) development and testing of efficient optimization methods; (8) sensitivity analyses; (9) Uncertainty Quantification for Design;(10)System Modeling and Discretization for Design, (11) Multi-Fidelity Analysis for Design.

AFRL-Aerospace Systems

Dr. Johnston, David
Assistant to the Chief Scientist
Aerospace Systems Directorate AFRL / RQ
Wright-Patterson AFB, Ohio 45433-7542
Email: david.johnston.17@us.af.mil