Reduction of shock-induced boundary layer separation in hypersonic inlets using bleed

Abstract

The proper design of the inlet system is of great importance for the performance of air-breathing hypersonic space planes. One of the dominating flow phenomena inside such a hypersonic inlet is the mutual interaction of oblique shocks with boundary layers, forcing the boundary layer to separate from the inlet wall. As a method to improve the inlet efficiency, the application of bleed is examined using a generic flat plate model and a single shock/laminar boundary layer interaction. By means of computational fluid dynamics as well as experiments in the hypersonic wind tunnel facility H2K of the DLR, favourable design parameters for the bleed set-up are presented and the efficiency of bleed for the reduction of the boundary layer separation and the thermal loads on the surface is demonstrated