Hypersonic Foundational Research Plan

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  • Canonical: …reduced to the simplest or clearest schema possible. (Webster’s Seventh New Collegiate Dictionary) The Shock Dominated Flows (SDF) thrust team had some initial difficulty defining its niche within the overall Hypersonic Basic Research Plan. Other thrust areas had responsibility for generating fundamental data for physical models that are critical in understanding hypersonic flow. Initially, the SDF team considered fundamental experiments that were not explicitly covered by other thrust areas (e.g. unsteady interactions, bodies in relative motion). It also considered some less “fundamental” flows that were still of interest to some part of the hypersonics community (e.g. hypersonic flow through a dusty gas as may occur for Mars entry, flow over an inflatable, flexible aerobrake). This approach of listing experiments not included elsewhere was unsatisfactory, potentially leading to a long, unfocussed list. This approach also ignored the critical role of simulation for design and innovation - a topic not covered in any other thrust area. The team eventually adopted the approach presented here based on the idea that there should be a “canon” of fundamental experiments available for validation of simulations in hypersonics. The experiments are intended to progressively include more realistic flow complexities while attempting to focus on one phenomenon at a time. The set of experiments by Mike Holden et. al. at CUBRC on the hollow cylinder flare and the sharp double cone that examined extent of separation, pressure and heating distributions as a function of Reynolds number and gas chemistry (non-reacting Nitrogen and reacting air) are considered examples of canonical experiments. The organization of this plan thus focuses on an outline of canonical experiments, an estimate of current simulation capability for that experiment, and a set of near, mid, and far term goals for advancing the simulation capability. Simulation capability metrics will be defined for the purposes of this evaluation. Hypersonic simulations frequently require applicability in domains ranging from continuum (mean free path much smaller than smallest length scale of problem) to free molecular flow (mean free path is much larger than characteristic dimension of vehicle). The transitional domain may be simulated using equation sets more general than Navier-Stokes. Modeling techniques like Direct Simulation Monte Carlo are theoretically applicable across all domains but require excessive resources in the continuum realm. Adaptive simulation, automated uncertainties - (ASAU) A robust simulation capability has the ability to start from an initial grid, automatically adapt the grid until a user specified grid convergence error is attained and automatically publish uncertainties associated with physical model parameters.
  • Canonical: …reduced to the simplest or clearest schema possible. (Webster’s Seventh New Collegiate Dictionary) The Shock Dominated Flows (SDF) thrust team had some initial difficulty defining its niche within the overall Hypersonic Basic Research Plan. Other thrust areas had responsibility for generating fundamental data for physical models that are critical in understanding hypersonic flow. Initially, the SDF team considered fundamental experiments that were not explicitly covered by other thrust areas (e.g. unsteady interactions, bodies in relative motion). It also considered some less “fundamental” flows that were still of interest to some part of the hypersonics community (e.g. hypersonic flow through a dusty gas as may occur for Mars entry, flow over an inflatable, flexible aerobrake). This approach of listing experiments not included elsewhere was unsatisfactory, potentially leading to a long, unfocussed list. This approach also ignored the critical role of simulation for design and innovation - a topic not covered in any other thrust area. The team eventually adopted the approach presented here based on the idea that there should be a “canon” of fundamental experiments available for validation of simulations in hypersonics. The experiments are intended to progressively include more realistic flow complexities while attempting to focus on one phenomenon at a time. The set of experiments by Mike Holden et. al. at CUBRC on the hollow cylinder flare and the sharp double cone that examined extent of separation, pressure and heating distributions as a function of Reynolds number and gas chemistry (non-reacting Nitrogen and reacting air) are considered examples of canonical experiments. The organization of this plan thus focuses on an outline of canonical experiments, an estimate of current simulation capability for that experiment, and a set of near, mid, and far term goals for advancing the simulation capability. Simulation capability metrics will be defined for the purposes of this evaluation. Hypersonic simulations frequently require applicability in domains ranging from continuum (mean free path much smaller than smallest length scale of problem) to free molecular flow (mean free path is much larger than characteristic dimension of vehicle). The transitional domain may be simulated using equation sets more general than Navier-Stokes. Modeling techniques like Direct Simulation Monte Carlo are theoretically applicable across all domains but require excessive resources in the continuum realm. Adaptive simulation, automated uncertainties - (ASAU) A robust simulation capability has the ability to start from an initial grid, automatically adapt the grid until a user specified grid convergence error is attained and automatically publish uncertainties associated with physical model parameters.
  • Hypersonic Foundational Research Plan

    1. 1. Comprehensive Technical Objectives Thrust Area Supersonic Combustion Boundary Layer Physics Shock-Dominated Flows Nonequilibrium Flows Environment-Material Interactions Material Dev. and Modeling <ul><li>Semi-empirical transition est. for mild 3-D flows </li></ul><ul><li>Characterize influence of flow chemistry on turbulence </li></ul><ul><li>Physics-based num. estimation of transition for actual systems </li></ul><ul><li>Flow control for optimization of the boundary layer </li></ul><ul><li>Identify critical reactions & comp. or measure key cross section </li></ul><ul><li>Identify new high-T reaction pathways – incl intermed. const. </li></ul><ul><li>Quantify regimes where kinetic methods required </li></ul>Near Term (2010) Mid Term (2020) Far Term (2030) <ul><li>Simultaneous diagnostic msmts </li></ul><ul><li>RANS-LES of combustor components </li></ul><ul><li>Thermal Control </li></ul><ul><li>On-Board Diagnositcs </li></ul><ul><li>Full Combustor LES </li></ul><ul><li>External Burning Aerodynamic Control </li></ul><ul><li>Component DNS </li></ul><ul><li>Full ground-flight scaling of tests </li></ul><ul><li>Fault-tolerant control </li></ul><ul><li>General finite-rate surface chemistry into CFD codes & loosely coupled equilibrium CFD with ablative material response </li></ul><ul><li>Surface msmt evaluation </li></ul><ul><li>In-situ surface composition and flux measurements </li></ul><ul><li>Validated surface chem models </li></ul><ul><li>Fully-coupled non-equilibrium CFD and material response </li></ul><ul><li>Fully-coupled, time-accurate boundary layer material response prediction </li></ul><ul><li>Engineered environ-mat’l int. for enhanced performance </li></ul><ul><li>Identify high-T react. and relax. rates </li></ul><ul><li>Complete collisional-radiative model for noneq radiative heat transfer </li></ul><ul><li>Fast CFD/kinetic/hybrid 3D simulation tools including complex effects </li></ul><ul><li>Complete multi-T and state-to-state reaction/relaxation models for gases of interest over full T range </li></ul><ul><li>Flight data and relevant ground test data with sufficient detail to validate models and tools </li></ul><ul><li>Define canonical expts to validate sim. </li></ul><ul><li>Promote hypersonic LES and DNS to advance understanding transition, turbulence, gas-surface interactions and gas-kinetics in shock dominated flows. </li></ul><ul><li>Define, prioritize, and execute new canonical experiments for validation </li></ul><ul><li>Mature simulation capabilities across Knudsen range including LES and high-T effects of rad. and ablat. with automated grid adaptation. </li></ul><ul><li>Maintain living canon of experiments with well defined metrics for simulations. </li></ul><ul><li>Mature multi-physics simulation capabilities with quantifiable uncertainties including coupled aero-material response. </li></ul><ul><li>Develop lab-scale test methodology to simulate flight conditions. </li></ul><ul><li>Identify test methods to accelerate screening and validation </li></ul><ul><li>Develop in-situ characterization tech. </li></ul><ul><li>Develop test methods for complex UHT composites with tailored structures. </li></ul><ul><li>Develop techniques to predict UHT properties from minimal samples at room temperature </li></ul><ul><li>Optimize tools to predict material response and performance across scales </li></ul><ul><li>Develop coupled multi-scale simulations of material response to extreme environments and loads. </li></ul><ul><li>Semi-empirical est. for large bluntness (reentry) vehicles and cones at AOA </li></ul><ul><li>Quantification of surface effects </li></ul><ul><li>Exploration of flow control: shaping/passive/active (thermal bumps?) </li></ul>
    2. 2. Comprehensive Technical Objectives: Laminar-Turbulent Transition Near Term (2010) Mid Term (2020) Far Term ( 2030) Thrust Area <ul><li>Semi-empirical estimation for mildly 3-D flows </li></ul><ul><li>Characterize impact of single discrete roughness elements </li></ul><ul><li>Idealized surface conditions </li></ul><ul><li>Semi-empirical estimation for large bluntness (reentry) vehicles and cones at AOA </li></ul><ul><li>Estimate impact of realistic roughness – isolated and quasi-random distributed </li></ul><ul><li>Exploration of flow control: shaping/passive/active (thermal bumps?) </li></ul><ul><li>Physics-based num. estimation of transition for actual systems, fully integrated within CFD solver </li></ul><ul><li>Viable Laminar Flow Control </li></ul>Overall Physics-Based Numerical Models Receptivity Modeling and Experiments Material/Surface Influence Facilities & Instrumentation <ul><li>Semi-empirical est. for mild 3-D flows </li></ul><ul><li>Transient growth theory </li></ul><ul><li>DNS for Receptivity and Breakdown </li></ul><ul><li>Semi-empirical est. for realistic flows </li></ul><ul><li>Transient growth models </li></ul><ul><li>Reduced order models for receptivity and breakdown/relaminarization </li></ul><ul><li>Expand range of application of transient growth </li></ul>Integrated numerical models for entire transition process, including laminar flow control methods <ul><li>Response to individual disturbances </li></ul><ul><li>Well-defined, controlled free-stream perturbation </li></ul><ul><li>Single isolated roughness element </li></ul><ul><li>Disturbance environment characterization in ground facilities </li></ul><ul><li>Receptivity models for complex disturbances </li></ul><ul><li>Measured flight dist environment </li></ul><ul><li>Response to multiple inputs </li></ul><ul><li>Distributed roughness field </li></ul><ul><li>Numerical prediction of receptivity for realistic aerothermodynamic environment, surface conditions and configurations </li></ul><ul><li>Start addressing </li></ul><ul><li>Impact of mfg tolerances </li></ul><ul><li>Influence of surface chem </li></ul><ul><li>Influence of surface blowing </li></ul><ul><li>Characterize realistic TPS surface conditions </li></ul><ul><li>Passive flow control – Ex. Ultrasonically Absorptive Coatings </li></ul><ul><li>Response to ablated surface condition </li></ul><ul><li>Modern blowing experiments </li></ul><ul><li>Stability calculations for 3D flows with chemistry and radiation </li></ul><ul><li>Active flow control via surface material interaction </li></ul><ul><li>Numerically predicted response to ablated surface with chemistry and blowing </li></ul><ul><li>High-freq P, T and Cf sensors </li></ul><ul><li>Advanced visualization techniques </li></ul><ul><li>Quiet facilities at M=3.5, 6 </li></ul><ul><li>Field measurement of instabilities </li></ul><ul><li>Next Gen Quiet Facility? </li></ul><ul><li>Packaged off-the-shelf hi-freq sensors </li></ul><ul><li>High-Enthalpy Quiet Facility? </li></ul><ul><li>Alternate gases (e.g., CO 2 ) </li></ul>Flight Experiments <ul><li>Moderate Mach, no chemistry </li></ul><ul><li>Simple SWTBLI </li></ul><ul><li>Series of affordable tests </li></ul><ul><li>Basic research at high M + chemistry </li></ul><ul><li>High-freq meas. of instabilities </li></ul><ul><li>Participate in T & E flight testing </li></ul>
    3. 3. Comprehensive Technical Objectives: Turbulent Boundary Layers Near Term (2010) Mid Term (2020) Far Term (2030) Thrust Area <ul><li>Validated RANS for attached TBLs </li></ul><ul><li>Robust LES for moderate Re with and without non-equilibrium effects </li></ul><ul><li>DNS of low Re with and without non-equilibrium effects </li></ul><ul><li>Validated closures for attached high enthalpy TBLs & separation/reattachment </li></ul><ul><li>LES Simulations of higher Re, high-enthalpy flows </li></ul><ul><li>Quantification of surface effects – catalycity and roughness </li></ul><ul><li>Validated full vehicle closure </li></ul><ul><li>Validated closure at re-entry conditions including surface catalysis and ablation </li></ul><ul><li>LES for full-scale capsule </li></ul>Overall Physics Based Modeling (RANS/Hybrid/DNS) Aerothermal Physics/Validation Experiments Facilities & Instrumentation <ul><li>RANS modeling framework for non-equilibrium flows including chemistry, roughness & surface degradation (e.g. ablation) </li></ul><ul><li>SGS models: high M, non-eq flows </li></ul><ul><li>High-order DNS solvers: complex geometry with non-equilibrium effects </li></ul><ul><li>Statistical measurements in canonical, high Mach flows including: </li></ul><ul><li>- Ablation/outgas effects </li></ul><ul><li>- film cooling </li></ul><ul><li>- Isolated protuberance/cavity effects </li></ul><ul><li>- Distributed roughness effects </li></ul><ul><li>Turbulent structure modification due to compressibility effects </li></ul><ul><li>Sep./reattachment/SWTBLI </li></ul><ul><li>Combined non-equilibrium, ablation & surface chemistry effects </li></ul><ul><li>High enthalpy roughness effects </li></ul><ul><li>Statistical turbulence measurements in true-enthalpy wind tunnels (expansion) </li></ul><ul><li>Turbulence measurements in flight </li></ul><ul><li>DNS experiments of basic phenomena including high enthalpy and surface chemistry </li></ul><ul><li>High-freq P, T and Cf sensors </li></ul><ul><li>Non-intrusive laser diagnostics for quantification of turbulent statistics </li></ul><ul><li>Visualization of low density flows </li></ul><ul><li>Small scale “clean” high-enthalpy Fac. </li></ul><ul><li>Develop national full-scale “clean” high-enthalpy facility </li></ul><ul><li>Non-intrusive techniques for short duration high-enthalpy flows </li></ul><ul><li>Flight test turbulence instrumentation </li></ul><ul><li>Packaged off-the-shelf hi-freq sensors </li></ul><ul><li>Moderate Mach, no chemistry </li></ul><ul><li>flight vs ground test for canonical flows </li></ul><ul><li>Correlate fight experiments with ground testing </li></ul><ul><li>Phenomenological RANS models for high Mach TBLs with & w/out roughness </li></ul><ul><li>LES implementation for moderate Re without non-equilibrium effects </li></ul><ul><li>Hybrid models for flow effectors </li></ul><ul><li>DNS database for low Re flows </li></ul><ul><li>Compressibility physics in fully 3D TBLs with non-equilibrium effects </li></ul><ul><li>2nd moment closure for all primary unclosed quantities </li></ul><ul><li>Heat transfer including catalysis/ablation </li></ul><ul><li>Simulation database for dist. roughness </li></ul>Flight Experiments <ul><li>Basic research at high Mach numbers </li></ul><ul><li>High freq. response instrumentation </li></ul><ul><li>Participate in T & E flight testing </li></ul><ul><li>Series of affordable tests </li></ul>Control <ul><li>Identification of high Mach number control mechanisms </li></ul><ul><li>Develop low-order control models </li></ul><ul><li>Experimental verification of mechanisms </li></ul><ul><li>Passive/active control at high enthalpy </li></ul><ul><li>Active control of turbulent flow structure including surface chemistry </li></ul><ul><li>Smart ablation </li></ul><ul><li>Demonstrate active control of an ablating system </li></ul><ul><li>Quantify basic turbulence statistics in flight </li></ul><ul><li>Fully validated full-scale ground testing at realistic enthalpies </li></ul><ul><li>Acquire detailed high-fidelity turbulence data for flight vehicles at realistic conditions </li></ul>
    4. 4. Comprehensive Technical Objectives: Shock Dominated Flows Define existing canonical expts to validate simulations Define and execute new canonical expts to validate simulations and physics models. Innovative BCs. Temporal tailoring of flow for design. Maintain living canon of expts. with well defined validation and performance metrics for simulations Thrust Area Near Term (2010) Mid Term (2020) Far Term (2030) Canonical Configurations - Blunt Body - Sharp Double Cone - Base Flows - Generic Scramjet FP - SBLI in channel - Hypersonic Piston Implement grid adaptation until user-specified convergence is achieved - Blunt Body: couple radiation effects, auto grid adaptation - Sharp Double Cone : coupled ablation - Base Flows: Coupled ablation, LES/DES methods - Blunt Body: couple transition estimation, multi-domain capability in Knudsen number - Sharp Double Cone : include transition estimation - Base Flows: Extend to transition estimation, radiation effects and multi-domain in Knudsen number Interactions - Flexible Ballute - Flat Plate - Fin - Bodies in Rel. Motion - Jet into Cross Flow - Flexible Ballute: User specified grid adaptation - Flat Plate - increased physical fidelity in all areas - Bodies in Rel. Motion: include equil. gas thermophysics - Flexible Ballute: coupled radiation, subscale models, generalized Kn range - Flat Plate - multi-domain Kn range - Bodies in Rel. Motion: noneq. gas thermophysics, unsteady sim., auto grid adapt - Flexible Ballute: fully coupled gas and mat'l physical response , auto grid adaptation - Flat Plate - fully resolved in gas physics, auto grid adaptation - Bodies in Rel. Motion: noneq. gas physics, subscale turb models, auto grid adapt Surface Effects - Microramps, Bleed, - Porous Wall, etc. Equil gas sim. for steady solutions Noneq. gas in unsteady soln w. user specified grid adapt Fully resolved turbulent scales Plasma Flow Noneq. gas sim with user specified grid adapt Incl unsteady solutions and auto grid adapt Incl Coupled radiation and fully resolved turb scales for generalized physical domain
    5. 5. Comprehensive Technical Objectives: Shock Dominated Flows Physics Complexity 1 - Perfect Gas 2 - Equilibrium Gas 3 - Thermochemical Nonequilibrium and/or Ionization 4 - Coupled Ablation 5 - Coupled Radiation 6 - Coupled Aero-Thermo-Elastic Material Response Knudsen Number Range 1 - Applicable in single domain, possible extensions using slip boundary conditions 2 - Multi-domain applicability enabled in single problem across manually specified interface 3 - Generalized equation set or automated, adaptive application of appropriate equation sets. Turbulence models 1 - Reynolds Averaged Navier Stokes (RANS) 2 - Unsteady RANS (URANS) 3 - Subscale models: (DES), and (LES) 4 - Coupled stability equations to predict transition 5 - Fully-resolved scales: (DNS) Adaptive simulation, automated uncertainties - (ASAU) 0 - Some automated adaptation 1 - Grid adaptation (enrichment, coarsening, alignment) proceeds automatically until user specified grid convergence error is attained. 2 - Grid adaptation proceeds automatically and uncertainties derived from physical model parameters are published. Thrust Area Near Term Mid Term Far Term Canonical Configurations Blunt Body ( 4 1 1 0 ) Sharp Double Cone ( 3 1 1 0 ) Base Flows ( 3 1 1 0 ) Generic Scramjet FP ( 3 1 1 0 ) SBLI in channel ( 3 1 1 0 ) Hypersonic Piston ( 3 1 1 0 ) ( 4 1 1 1 ) ( 3 1 1 1 ) ( 3 1 1 1 ) ( 3 2 1 1 ) ( 3 2 1 0 ) ( 3 2 1 0 ) ( 5 1 1 2 ) ( 4 1 1 1 ) ( 4 3 2 1 ) ( 3’ 2 1 1 ) ( 5 4 3 2 ) ( 4 4 1 2 ) ( 5 4 3 2 ) ( 3 3 1 2 ) ( 3 3 1 2 ) ( 3’ 2 1 2 ) Interactions Flexible Ballute ( 3 1 1 0 ) Flat Plate - Fin ( 2 2 1 0 ) Bodies in Rel. Motion ( 1 1 1 0 ) Jet into cross flow ( 3 1 1 0 ) ( 3 1 1 1 ) ( 3 3 1 1 ) ( 2 1 1 1 ) ( 3 1 3 1 ) ( 5 3 3 1 ) ( 3 3 2 1 ) ( 3 2 1 2 ) ( 3 1 3 1 ) ( 6 5 3 2 ) ( 3 5 3 2 ) ( 3 3 1 2 ) ( 3 5 3 2 ) Surface Effects Microramps, Bleed, Porous Wall, etc. ( 1 1 1 0 ) ( 2 1 1 1 ) ( 3 2 1 2 ) ( 3 5 1 2 ) Plasma Flow ( 3 1 1 0 ) ( 3 1 1 1 ) ( 3 2 1 2 ) ( 5 5 3 2 ) Define existing canonical expts to validate simulations Define and execute new canonical expts to validate simulations and physics models. Innovative BCs. Temporal tailoring of flow for design. Maintain living canon of expts. with well defined validation and performance metrics for simulations
    6. 6. Comprehensive Technical Objectives: Nonequilibrium Hypersonic Flows Near Term (2010) Mid Term (2020) Far Term (2030) Thrust Area Cross Sections and Thermochemical models Radiation, plasma, surface Models Facilities Noncontinuum Flows Transport Phenomena <ul><li>Identify key reactions and obtain cross sections </li></ul><ul><li>PES for key reactions </li></ul><ul><li>Nonequilibrium shock tube data </li></ul><ul><li>Uncertainty Analysis </li></ul><ul><li>Ro-vibration-Dissociation coupling Model </li></ul><ul><li>Internal energy relaxation model </li></ul><ul><li>Electron excitation rates </li></ul><ul><li>Detailed state-to-state cross section measurement </li></ul><ul><li>Rate constant measurements </li></ul><ul><li>Radiation measurements at 5-7 km/s flight for thermochemical model validation </li></ul><ul><li>Detailed Master equation simulations </li></ul><ul><li>Reduced reaction models </li></ul><ul><li>Transition probablities validation </li></ul><ul><li>VUV measurements for air and Mars </li></ul><ul><li>Collisional-Radiative model for air, Titan </li></ul><ul><li>Uncertainty Analysis </li></ul><ul><li>Line broadening meaurements </li></ul><ul><li>Radiation absorption by ablation products </li></ul><ul><li>Shock tube measurements at low pressure (p < 0.1 Torr) </li></ul><ul><li>CR model for Mars </li></ul><ul><li>Radiation model validation in LTE plasma </li></ul><ul><li>3D Radiation transport </li></ul><ul><li>Radiation measurements at 7-15 km/s flight for thermochemical model validation </li></ul><ul><li>CR Model for H2/He </li></ul><ul><li>Radiation in strongly ionized flows </li></ul><ul><li>Spatially resolved pitot/null point sweeps </li></ul><ul><li>LIF measurements (centerline, pointwise) </li></ul><ul><li>Expanding flow simulations </li></ul><ul><li>Velocity/turbulence measurements </li></ul><ul><li>Optical measurements of settling chamber </li></ul><ul><li>Contamination characterization </li></ul><ul><li>LIF measurements (spatially resolved) </li></ul><ul><li>Integrated arc-nozzle simulations </li></ul><ul><li>Radiative/convective coupling </li></ul><ul><li>Arc-heater simulation </li></ul><ul><li>Contaminant mitigation </li></ul><ul><li>Flight verification of ground based facility measurements </li></ul><ul><li>Combined radiative-convective facilities </li></ul><ul><li>Higher enthalpy facility ( > 45 MJ/kg) </li></ul><ul><li>Larger length scale facilities </li></ul><ul><li>Optimize arc-heater design (efficiency, heat transfer, flow path) </li></ul><ul><li>Hybrid methods </li></ul><ul><li>Preliminary algorithms for ionization in non-continuum flows </li></ul><ul><li>Studies to determine sensitivity of non-continuum effects for candidate missions </li></ul><ul><li>Advanced algorithms for ionization in non-continuum flows </li></ul><ul><li>Improved gas-surface and surface accomodation models </li></ul><ul><li>Improved performance for non-continumm simulations </li></ul><ul><li>Flight data for rarefied aerothermal environment </li></ul><ul><li>Exploitation of advanced computer architectures for non-continuum solvers </li></ul><ul><li>Transport in highly ionized flows </li></ul><ul><li>Thermal conductivity models in thermal nonequilibirum </li></ul><ul><li>Electron transport properties </li></ul><ul><li>Transport cross sections for ablation product interactions </li></ul><ul><li>Measure plasma properties in high speed flight </li></ul>TBD
    7. 7. Comprehensive Technical Objectives: Supersonic Combustion Thrust Area Near Term (2010) Mid Term (2020) Far Term (2030) Physical and Chemical Process Characterization Simultaneous - CARS/Rayleigh measurements (T,V species) Non-equilibrium plasmas (ignition and flame holding) Fuel characterization via surrogates On-board flight-capable diagnostics General thermodynamic, kinetic, & transport characterization of fuels. Coupled Subsonic/supersonic flame-holding control. Well characterized combustor environments for all relevant scales. Characterization of anisotropic turbulence mechanisms. Characterization of coupled mixing/heat release effects. Modeling and Simulation Tools Variable turbulent Pr, Sc models. EASM RANS turbulence models. Hybrid RANS-LES Novel algorithms & grid gen. Component (fuel injector) LES Combustor LES LES with enhanced reduced models. Multiphase combustion simulations Quantified uncertainties Time-dependent mode transition prediction Full flow path LES Component-level DNS Scaling “Laws” Database development for “1X” class components. Database development for “10X” class propulsion systems. Quantified uncertainties for “1X” class database. Development of multi-parameter scaling tools. Accurate extrapolation of ground-to-flight data (“100X”) Advanced Experimental Techniques Development of high resolution LITA in cold-flow environments Unification of experimentation, M&S, and diagnostics. Multiplexed tunable diode absorption spectroscopy (TDLAS) TDLAS tomography for combustion efficiency assessment in realistic environments. In-situ mass flow measurements. 2-D and 3-D multi-parameter measurements (PLIF, Raman) for P, T, Velocity. In-situ time-resolved multi-parameter measurements (combustion efficiency, skin friction, heat transfer, thrust) Active Control Thermal control via regenerative cycle. Exploration of optimal control approaches (AI vs. model-based) Combustion control via regulated fueling. Identification of instrumentation needs for control strategies. Optimized aero/propulsion system performance via fault tolerant control algorithms. Propulsion Airframe Integration Establishment of operability margins for inlet-combustor interactions. Application of external burning. Implement alternatives to control surfaces (i.e. MHD) Validated design tools and databases for efficient aero/propulsion integration.
    8. 8. Comprehensive Technical Objectives: Materials and Structures Near Term (2010) Mid Term (2020) Far Term (2030) Thrust Area <ul><li>Optimize current classes of materials including: window materials, high emissivity coatings, functional materials. </li></ul><ul><li>Explore modeling and simulation approaches for discovery of high temperature materials. </li></ul><ul><li>Develop computational tools for materials design. </li></ul><ul><li>Discover oxidation and thermal shock resistant hybrid UHT materials for use in dynamic, impact, and extreme environmental loading environments. </li></ul><ul><li>Discover materials that help to integrate and join UHT materials into complex composite structures with durable/predictable interfaces. </li></ul><ul><li>Optimize computational tools for materials design. </li></ul><ul><li>Develop robust models to predict mechanical performance of complex materials. </li></ul><ul><li>Develop computational tools to model time and environmental effects on microstructure and properties. </li></ul><ul><li>Discover UHT materials that are reusable in extreme environments. </li></ul>Materials Discovery Characterization: Thermal & Mechanical Property Evaluation <ul><li>Develop lab-scale test methodology to simulate actual hypersonic flight conditions. </li></ul><ul><li>Identify test methods to accelerate screening and validation of candidate materials.- </li></ul><ul><li>Develop in-situ materials characterization techniques that capture data across multiple length scales at high temperature. </li></ul><ul><li>Develop test methods for complex UHT composites with tailored structures. </li></ul><ul><li>Develop computational techniques to predict UHT mechanical properties from minimal sample sizes and volumes taken from room temperature data measurements. </li></ul><ul><li>Optimize material modeling and simulation tools to predict material response and performance across length and time scales. </li></ul><ul><li>Develop coupled multi-scale simulations of material response to extreme environments and loads. </li></ul>Processing & Manufacturing <ul><li>Develop a validated UHT materials property database. </li></ul><ul><li>Develop scale-up methodologies to enable manufacturability. </li></ul><ul><li>Assess analytical tools available for manufacture of realistic sized components. </li></ul><ul><li>Develop scalable, robust processing methodologies for complex, affordable UHT components. </li></ul><ul><li>Develop reliable processes for joining dissimilar materials with predictable long-term behavior under extreme environments. </li></ul><ul><li>Develop robust and cost effective methods for manufacturing computationally driven materials designs. </li></ul><ul><li>Develop computational based processing tools to enable total control of material composition and structure across length and time scales. </li></ul>Health Monitoring & Prognosis <ul><li>Identify system approach to local damage and repair. </li></ul><ul><li>Develop quantitative on-line manufacturing NDE techniques. </li></ul><ul><li>Develop sensors for monitoring damage progression throughout the structure in realistic environments including vibration perturbations, temperature/humidity changes, etc. </li></ul><ul><li>Develop self-repairing/healing technologies for reliability and reusability. </li></ul>
    9. 9. Comprehensive Technical Objectives: Environment-Material Interactions Near Term (2010) Mid Term (2020) Far Term (2030) Thrust Area <ul><li>Incorporate computational module for general finite-rate surface chemistry into CFD codes </li></ul><ul><li>Sensitivity analysis to identify critical processes and rates </li></ul><ul><li>Environmental barrier coatings </li></ul><ul><li>Experiments to measure critical rates and important species </li></ul><ul><li>Validate surface chemistry models against data from ground test facilities (shock tunnels, arc-jets, plasmatrons) </li></ul><ul><li>Test improved codes against flight experiments </li></ul><ul><li>Reaction rates determined from first principles (quantum mechanics) or large scale simulations (kinetic Monte Carlo) </li></ul><ul><li>Surface Chemistry </li></ul><ul><li>Surface catalysis </li></ul><ul><li>TPS-transforming surface reactions (passive oxidation and nitridation) </li></ul><ul><li>Active Oxidation </li></ul><ul><li>Ablation </li></ul><ul><li>Surface recession </li></ul><ul><li>Char layer formation </li></ul><ul><li>Pyrolysis gas chemistry </li></ul><ul><li>Melt formation/transport </li></ul><ul><li>Boundary Layer Interactions </li></ul><ul><li>Response to surface chemistry, mass injection, and shape change/ surface recession </li></ul><ul><li>Environment Tailoring </li></ul><ul><li>by Material Design (AF) </li></ul><ul><li>Passive and adaptive flow control </li></ul><ul><li>Benchmark SOA capability </li></ul><ul><li>Identify key mechanisms for select TPS materials </li></ul><ul><ul><li>Formulate improved models for in-depth chemistry, in-depth heat/mass transport, and melt formation/flow Multi-dimensional material response models (conduction and porous media flow)) </li></ul></ul><ul><ul><li>Composite ablators (multi-layer and aggregate) </li></ul></ul><ul><li>Experiments to measure key properties and parameters </li></ul><ul><li>Self-healing material systems </li></ul><ul><li>Incorporate improved models into thermal response codes </li></ul><ul><li>Validate codes against data from ground test facilities </li></ul><ul><li>Multiscale material modeling of the physics, chemistry, and morphology of an ablating TPS system </li></ul><ul><ul><li>Loosely Coupled Ablation Predictions using 1D mat’l response with 3D equilibrium CFD </li></ul></ul><ul><ul><li>Finite rate gas chemistry models for ablation product air interactions </li></ul></ul><ul><ul><li>Blowing and roughness boundary-layer modeling </li></ul></ul><ul><li>Fully-Coupled, quasi-static Ablation Predictions using 3D mat’l response with 3D non-equilibrium CFD </li></ul><ul><li>Prediction of surface morphology </li></ul><ul><li>Fully-coupled, time-accurate boundary layer material response prediction, including surface morphology </li></ul><ul><li>Concept & feasibility studies </li></ul><ul><li>Ultrasonically Absorptive Coatings </li></ul><ul><li>Boundary Layer Stabilizing Additives </li></ul><ul><li>Ignition/Combustion enhancers </li></ul><ul><li>“ Smart ablator” – release of energy absorbing species </li></ul><ul><li>Passive and adaptive flow control via surface material interaction </li></ul><ul><li>Experimental Tools </li></ul><ul><li>Surface composition and morphology </li></ul><ul><li>Species flux diagnostics </li></ul><ul><li>New facilities and flight expts </li></ul><ul><ul><li>IInvestigate in situ methods to probe surface composition, emittance, and roughening </li></ul></ul><ul><ul><li>Investigate intrusive (near surface mass spec) and non-intrusive (emission and laser spectroscopic) methods to measure species fluxes to and from surfaces </li></ul></ul><ul><ul><li>Improved testing techniques (shear, </li></ul></ul><ul><ul><li>Characterization of arc jet flow field species at discrete locations </li></ul></ul><ul><ul><li>Techniques to characterize arc jet flow field chemical physics </li></ul></ul><ul><ul><li>Demonstrate in situ measurements of surface composition, emittance, and roughness during facility tests </li></ul></ul><ul><ul><li>Demonstrate species flux measurements during facility tests on reusable and ablating TPS </li></ul></ul><ul><ul><li>Pyrolysis test bed to isolate physical and chemical processes </li></ul></ul><ul><ul><li>Experimental methods to validate chemical kinetics and gas transport </li></ul></ul><ul><li>Incorporate new measurement techniques as routine diagnostics during all TPS tests </li></ul>Overall <ul><li>General finite-rate surface chemistry into CFD codes & loosely coupled equilibrium CFD with ablative material response </li></ul><ul><li>Surface measurement evaluation </li></ul><ul><li>In-situ surface composition and flux measurements </li></ul><ul><li>Validated surface chemistry models </li></ul><ul><li>Fully-coupled non-equilibrium CFD and material response </li></ul><ul><li>Fully-coupled, time-accurate boundary layer material response prediction </li></ul><ul><li>Engineered environment-material interactions for enhanced performance </li></ul>

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