Unsteady evolution of distributed roughness-induced vortices under re-entry conditions

Abstract This study investigates a re-entry scenario of an Apollo-like space capsule with Direct Numerical Simulations (DNS). The simulation includes the chemical equilibrium gas model. Cross-flow-like vortices are induced through random distributed roughness patches on surface. Two different machine learning methods used to predict maximum vorticity magnitude downstream pseudo-random patch, wall-normal location vortex core and spanwise gradient maxima u . A large DNS database is formed for training testing neural networks. In order understand influence transition process, local one-dimensional inviscid (LODI) relations describe perturbations at inflow. disturbance evolution in streamwise direction analysed two-dimensional Fourier transformation time space. We show how magnitudes cross-flow-like vortices, derivatives velocity location.