Performance of wall-modeled LES on the planetary entry of vehicles

The high Mach and Reynolds numbers that appear during hypersonic entry create strong shocks and highly turbulent flows. In this talk, we explore improvements in turbulence modeling of wall-modeled Large Eddy Simulations (WMLES) for predicting quantities of interest in entry vehicles and compare the results with other methods such as Reynolds-averaged Navier–Stokes (RANS) simulations and experiments. This allows us to detect new flow physics during Martian entry that were not predicted before with steady RANS, namely a Kelvin-Helmholtz instability that interacts with the bow shock, and substantially different turbulent wake structures. We also investigate the entropy discontinuities across shock waves and the role of the shock-capturing scheme. It is observed that hypersonic Mach numbers tend to challenge conventional shock-capturing algorithms, causing incorrect vorticity propagation into the streamlines after the shock.