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Kyle Thompson

Publications and source records attributed to Kyle Thompson.

Assessment of Radiation Scattering by Dust in Mars Entry

The impact of gas phase radiation scattering by dust particle presence in Mars entry scenarios is assessed using a suite of numerical tools. A hypersonic gas and dilute particle multiphase flow is simulated using a mixed continuum model and an efficient size distribution quadrature scheme. Radiative transport is simulated with a hybrid ray-tracing and P1 spherical harmonics model. The NASA HARA radiation code and a Lorentz-Mie scattering model are used to predict the gas-particle mixture radiative properties. Application of the numerical suite to a representative case based on the Mars 2020 entry shows that, even at conditions in excess of the strongest recorded dust storm, the augmentation in surface radiative heat flux due to scattering alone is lower than 1%, and therefore negligible. Predictions with even higher dust loading conditions confirm that even highly uncertain dust mass profiles are unlikely to be a concern for the scattering augmentation mechanism.

Andrew Hinkle↗

Radiation Interaction with Particulates in Planetary Entry Flows

A hypersonic particle phase solver based on a continuum model is implemented in the NASA HyperSolve CFD code and used to predict particle phase conditions in a dusty Mars entry scenario. Black-body radiative emission from high temperature dust particles is predicted for a Mars relevant entry problem, and the emission integrated to an entry vehicle using a ray tracing approach to estimate surface heat flux. The surface heating due to this mechanism is found to be small relative to convective and radiation from the gas phase emission. Additionally, the effect of atmospheric haze particulates vaporizing in the Titan atmosphere is studied. The increase in carbon availability due to the composition of the haze particles is found to increase the gas radiative heating to the vehicle by up to 3% on the forebody of a representative Titan entry vehicle with approximately 0.15% haze in the freestream by mass.

Andrew Hinkle↗

Improvements to the LAURA Mesh Adaptation Algorithm

This paper describes recent improvements to the LAURA code that removes the requirementof unbroken body-normal lines when using the automated mesh adaptation algorithm inLAURA responsible for mesh alignment with shock and adjusting near-wall mesh spacing. Fornon-simple geometry, restricting block topologies such that blocks span the domain from thesurface wall boundaries to domain inflow boundary can be difficult or impossible. Removing thisrequirement enables novel block topologies that simplify the meshing workflow for LAURA users.The new adaptation algorithm implementation in LAURA is described and several examples ofthe adaptation are presented to demonstrate the efficacy of the adaptation algorithm.

LAURA↗

GPU Acceleration of VULCAN-CFD

This work presents a comprehensive overview of recent advancements in the application of GraphicsProcessing Units (GPUs) to accelerate the NASA-developed VULCAN-CFD code for hypersonic flow sim-ulations. The unstructured solver in VULCAN-CFD is undergoing a significant rewrite from modern Fortranto C++, enabling its execution on both GPUs and CPUs through the utilization of Kokkos, a programmingmodel for performance portability developed by Sandia National Labs. The paper outlines some modifica-tions that were made in the original implementation of VULCAN-CFD in order to harness the computationalpower of GPUs. Finally, we demonstrate performance improvements achieved through GPU acceleration.The accelerated code throughput on one GPU is shown to match approximately 200 CPU cores for bothsingle species and multi-species reacting cases.

Matthew O'Connell↗

Validation of the HyperSolve CFD Solver for Entry Descent and Landing Applications

The functional equivalence of the HyperSolve unstructured edge-based, finite-volume computational fluid dynamics code to the Langley Aerothermodynamic Upwind Relaxation Algorithm multiblock structured grid code is documented for applications of interest to the Entry, Descent, and Landing community. A suite of cases using a range of thermochemical gas models on relevant vehicle configurations were analyzed with both codes and the results compared. A tolerance of ±4% difference in surface pressure and surface heat flux from a benchmark LAURA solution was used as the criterion for functional equivalence, and comparisons of flowfield quantities are also included to verify that the thermochemical nonequilibrium capabilities in HyperSolve match those of the LAURA code. The functional equivalence of the HyperSolve unstructured edge-based finite-volume computational fluid dynamics (CFD) code to the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) multiblock structured grid code is documented for applications of interest to the Entry, Descent, and Landing (EDL) community. A suite of cases using a range of thermochemical gas models on EDL-relevant vehicle configurations were analyzed with both codes and the results compared. A tolerance of ±4% difference in surface pressure and surface heat flux from a benchmark LAURA solution was used as the criterion for functional equivalence, and comparisons of flow field quantities are also included to verify that the thermochemical nonequilibrium capabilities in HyperSolve match those of the LAURA code. In general, HyperSolve predictions for surface pressure and surface heat flux are in close agreement with those predicted by LAURA.

hypersolve↗