Ongoing work using SU2 for hypersonic applications�

Kyle Hanquist, Gohar Khokhar, Aaron Larsen, Martin Liza, Avery White, Leif Nelson-Melby, Sydney Schmidt, Daniel Fraijo, Shelby Horth, Ana Tuba

Garbacz, et al, 2021 SU2 Conference

Computational Hypersonics and Nonequilibrium Lab.

CHANL is active in the development and application of physical models and computational methods for simulation of complex phenomena such as nonequilibrium and reactive flows experienced during hypersonic flight.

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Adapted from J. Urzay, 2020

Wright, et al, RTO-EN-AVT-142, 2007

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SU2-NEMO (NonEquilibrium MOdels)

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• Extension of SU2 for nonequilibrium, high-temperature, and high-speed flows
• Continuum/slip regime, steady/unsteady, viscous/inviscid, multi-component, gas mixtures in thermochemical nonequilibrium
• Inherits a lot of strengths from SU2 (turbulence models, design, multiphysics, blowing)
• Coupled to Mutation++ for thermochemical models
• Extending to gas surface interactions and material response (ablation)
• Close collaboration with Stanford, Strathclyde, and VKI

Maier, et al, AIAA Paper 2023-3488

Chemical Kinetics

Aaron Larsen

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Vibrational State-to-State Modeling

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O₂-Ar bound-bound log(rates) at 3000 K

Streicher, et al, Physics of Fluids, 2020

Shock Tubes

• Shock tubes and especially reflected shock tubes are used to assess high-fidelity chemical kinetic approaches 
• Assumptions are made when modeling the shock tube (e.g., heat bath) = uncertainty 
• Are discrepancies due to assumptions or chemical kinetic data/approaches?
• Experimentalists also make assumptions when extracting shock tube data = uncertainty
• Goal: reduce this uncertainty

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Aero-Optics

Leif Nelson-Melby, Gohar Khokhar, Martin Liza

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Aero-Optics

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Oxygen at Mach 8

Liza, et al, AIAA Paper 2023-3736

Funding from AFRL Summer Faculty and

Army Research Office

Aero-Optics

• Partnering with University of Notre Dame hypersonic wind tunnel
• CFD analysis to guide design of a fundamental shape to optimize for transitional flow
• Aero-optical distortion calculations from CFD (future)
• Experimental comparison with Notre Dame wind tunnel data (future)

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Conditions: Re’ = 11.78 M/m, M = 5.7​​

N factor envelope from linear stability theory

Propulsion

Gohar Khokhar

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Solid Fuel Ramjets

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• ONR funded project in collaboration with UMBC and NAWS China Lake
• The goal is to regulate thrust in an SFRJ via variable bypass ratio
• Controller is adaptive but is more effective if we can tune it via theory and simulation
• Analytical theory + chemical equilibrium (NASA CEA)
• SU2: inviscid, RANS, LES
• Challenging physics:
• Adaptive geometry
• Combustion
• Solid fuel grain

Oveissi, et al, AIAA Paper 2024-0743

Solid Fuel Ramjets

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Plasma Flows

Shelby Horth, Ana Tuba

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Plasma Generation

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Electron Transpiration Cooling (ETC)

Aerodynamic Heating

Avery White, Sydney Schmidt

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Aerodynamic Heating

• Collaboration with experimental groups to verify and validate data for various aerodynamic shapes (cylinder, finned projectiles)
• Investigating initial cell size needed to get a grid-independent solution
• SU2 requires a small cell size for high-speed flows
• A small cell size hurts convergence
• Exploring various viscosity models to accurately calculate transport properties for low-temperature conditions

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Flow along Cylindrical Model

Heat Flux Results Along Stagnation Line for

 Various Initial Cell Sizes

Assessment and Validation Cases

Daniel Fraijo, Avery White

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Assessment and Validation Cases

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Translational (a) Rotational (b) Vibrational (c)

Physics of Fluids, (2023) 35 (8), 086106

Calculating Translational Temperature  with SU2 NEMO

Uncertainty Quantification

• Funded by NASA Kennedy Space Center and AI Solutions
• Quantify uncertainty in CFD simulations over space launch vehicles
• Goal is to create a plugin that works with any CFD solver
• Using first-order first moment and first-order second moment uncertainty quantification methods
• Easily expanded to multiple input parameters and low computational expense
• Test cases based on United Launch Alliance's Vulcan Centaur launch vehicle and Rocket Lab's Electron launch vehicle

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Looking forward

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Multi-physics coupling for a multi-physics environment

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Fluid solver

SU2

Chemical kinetics and transport properties

Mutation++

Material response solver

PATO?

Electromagnetic solver

TBD

Fluid state variables

Source terms, transport properties, thermodynamics

Heat flux, pressure, species fluxes

Blowing rate, temperature,

species mass fractions, surface movement

Structural solver

SU2/NASTRAN

Future Work

Functional

Joule heating,

Lorentz force

Electric conductivity

Heat flux, surface forces

Structural response

Design optimization,

Adjoint (sensitivity)

Turbulence models,

Fluid models,

Surface/mesh movement

Fluid-Thermal-Structural Interactions

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Huang, et al, Journal of Fluids and Structures, 2022

Meshing

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• Structured – Aerodynamic Heating
• Hybrid
• Mesh adaptation

• Pointwise
• GridPro
• Link3D
• GMSH

Garbacz, et al, 2021 SU2 Conference

Summary

• Hypersonics is complex and multi-physics which is SU2 is well suited for
• Still needs some improvements/enhancements
• Implicit solver
• Aerodynamic heating
• Turbulence models/aerodynamic heating

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Needels, et al, AIAA Paper 2022-1613

Comparisons to HyMETS facility

Acknowledgements

• NEMO Collaborators
• University of Strathclyde
• Stanford
• VKI
• SU2 developers
• Funding for this work
• Army Research Office
• NASA Kennedy / a.i. Solutions
• Office of Naval Research

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Questions/discussion

chanl.arizona.edu

hanquist@arizona.edu

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Backup slides

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Gas Surface Interactions

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Needels, et al, AIAA Paper 2022-1613

Comparisons to HyMETS facility