Particle Impingement Simulations for First and Second Mode Dominated High-Speed Boundary Layers

High-speed vehicles traveling through the atmosphere at supersonic or hypersonic speeds can encounter particles suspended in the freestream environment. These particles can impinge on the surface of these vehicles and introduce disturbances inside the boundary layer initiating the transition process from laminar to turbulent flow. Direct numerical simulations have been performed to investigate the particle induced transition process for three different flow scenarios: a M=4 flow over a 14 degree wedge with different wall temperatures Twall=823.4K and Twall=300K as well as a M=9.5 flow over the same geometry with a wall temperature of Twall=300K. These flow conditions were chosen to study the differences in the particle induced transition process for first and second mode dominated transitional boundary layer flows. The main focus of this work is on the receptivity process for the different flow conditions which is studied by employing bi-orthogonal decomposition of the flow field.