Toward physically realistic ablation modeling in direct simulation Monte Carlo

Abstract

The ablation of solid objects embedded in hypersonic flows can be simulated via the direct simulation Monte Carlo method. However, current ablation algorithms can suffer from numerical and geometric issues which distort the receding surface. This in turn can affect near-surface flow behavior and the overall ablation rate. To minimize these effects and enable more physically realistic ablation models, two algorithmic modifications are proposed here. The first is to store multiple values in each grid cell surrounding the surface so that the Marching Cubes algorithm (which triangulates the surface from the grid values) can be made more accurate. The second is to adjust grid values (due to collisions and reactions) in a mass-flux-preserving manner by decrementing multiple grid values simultaneously. Several ablation test cases are simulated to illustrate the effect of these enhancements.