Verification and Validation of Immersed Boundary Solvers for Hypersonic Flows with Gas-Surface Interactions

Abstract

During atmospheric entry, the flow environment around capsules or space debris is characterized by complex fluid thermochemistry and gas-surface interactions (GSI). Computational fluid dynamics (CFD) simulations of these conditions are crucial in the design process of such objects. A promising approach for the simulation of complex geometries is the use of immersed boundary methods (IBM) and adaptive mesh refinement techniques (AMR). These methods offer reliable and efficient mesh generation and adaptation with minimal user intervention. To that end, this paper presents the recent developments of two IBM-AMR solvers coupled with the same external thermochemistry library for the accurate modelling of such complex flows including GSI. Several verification and validation cases are presented, which demonstrate the performance of the solvers. Results are analyzed in comparison with a body-conforming solver that uses the same thermochemistry library to achieve a consistent assessment of the underlying numerical methods. A good agreement between all the solvers is indicated with certain discrepancies arising due to the differences in surface treatments.

Fluid Ablation Interactions on a Compression Ramp at Mach 8

“…This approach accurately accounts for cells being split by boundaries by considering the cut-elements that form from the intersection of the Cartesian grid and the surface geometry triangulation. Details of this method and its extension to catalytic and ablative immersed boundaries have been presented by Başkaya et al [46,47].…”

“…INCA considers a gas-surface interaction (GSI) boundary condition, while CHAMPS is coupled with a material response (MR) solver. Both the GSI [46,47] and MR [39] methods have been described and successfully demonstrated in several reference works. Here, only the differences within the approaches are discussed.…”