The document discusses progress and challenges in foundational hypersonics research. It notes that hypersonic flight requires integration across multiple disciplines including aerodynamics, materials science, and combustion. Recent accomplishments include unprecedented insights from large-scale simulations and optical diagnostics, as well as international partnerships providing opportunities for scientific flight research through programs like HIFiRE. Ongoing challenges include fully understanding nonequilibrium phenomena at small scales and limited access to hypersonic flight environments for testing.

1. AFOSR Progress and Challenges in Foundational Hypersonics ResearchApril 2011 John D. Schmisseur Program Manager AFOSR/NA Air Force Office of Scientific Research Thanks: Mike Wright, Jim Pittman, and Deepak Bose - NASA

2. Hypersonic Flight: Challenging Science & Integration Hypersonic: High-speed flow regime where energy transfer between the flow and thermodynamic and chemical processes becomes significant Development of Hypersonic Capabilities Requires the Integration of Contributions from a variety of Disciplines Advanced Sensors and Communications High-Temperature, Light, Durable Materials Enhanced Ignition and Combustion Innovative Flowpaths Advanced Numerical Simulations and Diagnostics Image Courtesy Kei Lau, Boeing Thermal Management Optimized Aerodynamics and Flow Control Advanced Flight Controls, Closed-Loop Optimization Control

4. 3 Science Centers

7. Focus is on Advanced Numerics

9. Challenges and opportunities

10. Recent accomplishments

12. Ensure the long-term availability of an expert knowledge base

13. Prepare for planned future hypersonic capabilities

14. Adopted by the JTOH as the basic research roadmapObjective: Advance Science to Address Critical Phenomena in 6 Thrust Areas Nonequilibrium Flows Shock-Dominated Flows High-Temperature Materials & Structures Environment-Structures & Material Interactions Supersonic Combustion Boundary Layer Physics

15. Near Term (2010) Semi-Empirical (Calibrated) Methods for 3-D Flows on Idealized Surfaces Far Term (2030) Physics-Based (Uncalibrated) Estimation for Actual Systems Mid Term (2020) Extend Semi-Empirical Methods to Account for Realistic Surface Conditions NHFRP Goals: Boundary Layer Physics Orbiter experiments facilitate characterization of real surface effects AFRL HIFiRE 1- March 2010 Axisymmetric Experiment NASA HyBoLT – 2008- Flat with crossflow on sides – lost during launch Simulation – artificially tripped Increasing 3-D Complexity HYTHIRM: Near IR Image of Shuttle Orbiter ~ Mach 9 AFRL HIFiRE 5 – 3-D Geometry with significant crossflow Responsive Space Access Continuous transition to tech maturation Prompt Global Strike Planetary Entry

16. Hypersonic Academic Research Partnership (HARP) Network of Academic Hypersonic Research Centers Uncertainty Quantification & Verification and Validation (NNSA) Application-Oriented (NASA ESMD) Multidisciplinary Science and Transitioning 6.1 Basic Science (AFOSR/NASA) AFRL/RB Midwest Structural Sciences Center at U. Illinois NHSC: Hypersonic Materials and Structures, Teledyne Scientific and Imaging Joint AFOSR-NASA Fundamental Aeronautics Sponsored National Hypersonic Science Centers Extend Collaboration Initiated Under the Foundational Research Plan Total of $30M in invested over 5 years U. Texas - Predictive Engineering and Computational Sciences (PECOS) Atmospheric Reentry Coordinating over $20M in Annual Investment Across DoD, NASA, DoE/NNSA and ASRP CUIP Reentry Aerothermo-dynamics Portfolio MURI: Fundamental Processes in High-Temperature Gas-Surface Interactions NSSEFF: Candler Thermophysics Scientific Disciplines Stanford University: The Center for Predictive Simulations of Multi-Physics Flow Phenomena with Application to Integrated Hypersonic Systems NHSC: Hypersonic Laminar-Turbulent Transition, Texas A&M AFRL/RB Computational Hypersonics Center at U. Michigan HIFiRE NHSC: Center for Hypersonic Combined Cycle Flow Physics, UVa ASRP: Scramjet-Based Access to Space – UQ consortium Research Objectives

21. a few come close…

22. Flight Research seems to be a lost art

24. Current interests: cyber-tech, socio-cultural, efficiencySimulation from H. Fasel, U. Az. Glass-Forming Ablator in Shear Courtesy Mike Wright, NASA Ames hn Vibrational Rotational Electronic

27. 230M element solution in 12-24 hours on 288 nodes

29. International Partnership Provides Opportunity for Scientific Flight Research Integrating All Resources HIFiREHypersonic International Flight Research Experimentation Risk reduction Demonstrated flight software Flight Research $56M AFRL/Australian DSTO Collaborative Effort for Flight Research Exploring Critical Fundamental Phenomena Experiment Computation HIFiRE-0 May 2009 HIFiRE-1 Mar 2010 BLT SBLI TDLAS HIFiRE-5 3D BLT 9 Flights Exploring Critical Science

30. International Partnership Provides Opportunity for Scientific Flight Research HIFiRE Flight 1 provides unprecedented insight into unsteady phenomena R. Kimmel and D. Adamczak, AFRL/RB Shock/Boundary Layer Interaction Laminar-Turbulent Transition Co-ax TC < 10 Hz VatellHT 1 kHz Wind Tunnel Schlieren Preliminary Results: Both transition and SBLI data reveal intermittent signals. Believed to be first such flight measurements for both phenomena. Tunnel Expt- Dolling and Murphy Note: Dissimilar Scales

36. Computations reproduced instability and identified source

38. Creating New Testing Capabilities Recent-Developed Basic Research Methods Rapidly Transitioned to Revolutionize Ground Test of Major National Programs J. Lafferty/ AEDC, G. Candler/ U. Minn. and S. Schneider / Purdue Falcon HTV-2 Low-Frequency Acoustic Pitot Probe High-FrequencyAcoustic Pitot Probe Focused schlieren image of BL transition obtained on 7° transition cone at Mach 10, Re/L = 2.0×106/ft Temperature Sensitive Paint Integrated Computations and Experiments provide unprecedented insight into sources and impact of critical aerothermodynamic phenomena PrimaryTest Article Auxiliary Model Support High-Fidelity Numerical Methods yield detailed insight into physics Innovative fluctuation measurements - Purdue Temperature-Sensitive Paint provides global heating Hemisphere Heat-Transfer Probe Purdue /SandiaTransitionCone AEDC U. Minn. AEDC Tunnel 9

40. High-fidelity ablator model formulated at the macroscopic scale

41. Implementation in PATO-modular 3D CFD toolbox

43. Second release of PATO with UQ module: October 2012

44. Coupling to hypersonics CFD tools: Oct. 2013

45. Full release of the high-fidelity PATO suite in Oct. 2014.Monte-Carlo simulation : Oxidation of the char layer of a low density carbon/phenolic composite (Stardust’s peak heating conditions) PATO simulation : Ablation of a PICA cylinder, 1MW/m², 30 seconds, NASA Ames X-Jet (off-centered)

47. Incorporation of additives for tailored properties

49. Modify polymer resin systems for increased flexibility

50. Incorporate endothermic additives and radiation inhibitors

51. Utilize multi-scale modeling to inform processing and design approaches for advanced TPSConventional Configurations

53. Train reactive force field for MD simulations of post-shock wave flows and gas-surface interactions

54. Extend to continuum models with DSMC models and state-specific simulations

55. Perform experiments at all scales to provide validation data for model generationReactive Force Fields Material Surface Effects High-Fidelity, Large-Scale CFD University of Minnesota, Penn State University, Montana State University, University of Arizona, and University of Buffalo

57. Higher moments, such as vorticity or enstropy can behave differently

58. Intermittancy is suppressedOrion Nebula

59. Changing the Technology Paradigm An Opportunity for Transformation Surface Heat Transfer Equation diffusive transport of chemical energy transport of thermal energy Improve models for energy transfer Control T via energy management Reliable models for Gas-Surface Interactions Control the gradient via boundary layer management Instability Acoustic Absorption How can we actively control energy transport to optimize system performance?

60. Exploring Transition Control Via Energy Transfer to Internal Modes Transition Delay Resulting from CO2 Injection in Boundary Layer Provides Potential Mechanism for Control CO2 Injection I . Leyva, AFRL/RZ J. Shepherd and H. Hornung, Cal Tech CO2 Transition Re* is about 4X that of Air and N2 For CO2 internal energy and acoustic instability modes overlap CO2 Curves for 3 total enthalpy values Acoustic Absorption CO2 Air & N2 2nd Mode Instability (Acoustic) Air From Hornung, H.G., Adam, P.H., Germain, P., Fujii, K., Rasheed, A., “On transition and transition control in hypervelocity flows,” Proceedings of the Ninth Asian Congress of Fluid Mechanics, 2002

61. Exploring Transition Control Via Energy Transfer to Internal Modes Porous Injector Results (10 MJ/kg): CO2 Delays Transition CO2 injection at 11.6 g/sec Laminar Flow past Re = 5.22 x 106 Zeroinjection Transition at Re = 4.12 x 106 Ar injection at 11.6 g/sec Transition at Re = 2.88 x 106 Turbulent Heating Correlations Non-dimensional Heat Transfer(St) Measured Heat Transfer Transition Transition Laminar Laminar Heating Reynolds Number based on distance from nose tip

63. Agencies and countries are actively collaborating

64. National Hypersonic Foundational Research Plan

65. HIFiRE

66. NATO RTO working groups

67. High-fidelity, large-scale numerical simulations and laser-based diagnostics are changing the game

68. Breakthrough science is impacting technology maturation

69. Look for the exploitation of rate-dependent energetic processesThank You!