Cross-Flow Phenomena in Streamline Traced Hypersonic Intakes

Abstract

Generally, the shape of streamline-traced intakes is defined by stream surfaces based upon an inviscid template flow field but corrected by appropriate local boundary layer displacement thicknesses. However, this design methodology neglects secondary effects such as the occurrence of cross-flow phenomena or local flow separation bubbles, which can lead to significant degradation of the overall intake performance. The present paper investigates the occurrence of cross flow phenomena within the boundary and entropy layers of a small scale stream-traced intake of a scramjet vehicle. The cross-flow was not anticipated during the design process and leads to a local accumulation of decelerated fluid near the combustor entrance. This effect lowers the margin against possible boundary layer separation and intake unstart. It is found that the cross-flow is mainly driven by inviscid phenomena principally linked to the presence of blunt leading edges.