Numerical Investigation of Hypersonic Boundary-Layer Stabilization by Porous Surfaces

Abstract

The acoustic second-mode instability predicted by linear stability theory is compared with direct numerical simulation for a hypersonic flow over various porous walls. The damping effect of the micropores on the second mode is shown by comparison of the two different approaches. In addition to investigating the effect of pore size, the influence of the pore shape is studied by using spanwise grooves and cylindrical pores. Specifically, the comparability of different pore shapes by two definitions of hydraulic diameter is analyzed. The influence of rarefied gas behavior of the flow inside the pores is also investigated by comparing a slip boundary condition with finite Knudsen numbers with a nonslip boundary condition for different radii and pore depths.