A two-dimensional strand/Cartesian Adaptive Mesh Refinement solver for automated mesh generation around hypersonic vehicles

Abstract

The design of an efficient Thermal Protection System (TPS) for a hypersonic vehicle will often require the use of computational simulations at the expected operating conditions. For accurate heating predictions, the computational mesh must adequately resolve the shock structures and boundary layer. Manually refining and updating the mesh in a through-trajectory simulation can consume a large amount of resources as the freestream conditions change and the body may ablate. As such, there is a need for automated mesh generation techniques that can sufficiently resolve the shock structures and boundary layer region.

In this work a two-dimensional strand/Cartesian Adaptive Mesh Refinement (CAMR) solver has been developed within the AMROC framework. The solver combines two highly-automated meshing methods - the CAMR method in the off-body region and the strand mesh method in the near-body region - using overset grid assembly techniques. A hypersonic fluid model and mapped mesh methods have been implemented to enable hypersonic simulations on strand mesh domains. Implicit and Implicit/Explicit methods, specifically developed for the highly-stretched strand grids, have been added to AMROC and their efficiency assessed. A novel strand meshing technique that gives better mesh quality close to the wall has been developed and coupled to a strand-surface deformation algorithm. Finally, an overset grid assembly library that takes advantage of the specific characteristics of the strand and CAMR meshes has been implemented and tested.

Test cases show that the strand/CAMR method is able to capture dynamic shock structures and give accurate heating results, including in cases where shocks cross the overset boundary and impinge on the surface. Simulations of recessing TPS surfaces and free-body motion demonstrate the automated meshing capabilities of the solver. Novel investigations of unsteady, hypersonic flows are carried out using the new solver. The strand/CAMR method is shown to enable automated simulations of complex hypersonic flows and could reduce the resources required for TPS analysis.

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Identifiers

ORCID for Chay William Charles Atkins: orcid.org/0000-0001-9243-4903

ORCID for Ralf Deiterding: orcid.org/0000-0003-4776-8183

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