Boundary Layer Bleed in Hypersonic Inlets.

Abstract

Shock-induced boundary layer separation has an important influence on the efficiency of hypersonic inlet systems. A method to reduce the boundary layer separation is the implementation of boundary layer bleed. Results are presented for the use of a planar bleed slot at a generic flat plate model for laminar boundary layer flow at a Mach numer of 6. The wind tunnel models and the wind tunnel test procedure are optimized by using computational fluid dynamics. An analytical method to predict the key parameters of the boundary layer bleed is presented. The possible reduction of the boundary layer separation and of the thermal loads on the walls by using bleed is demonstrated by results of wind tunnel tests and favorable design parameters for bleed slots are determined.