Cross-Flow Phenomena in Streamline Traced Hypersonic Intakes

Kurzfassung

The shape of streamline-traced intakes is defined by stream surfaces from an inviscid template flow field. Appropriate boundary layer corrections, i.e. local displacement thickness, are subsequently applied to the inviscid shape. This design methodology neglects, however, secondary effects such as the occurrence of local flow separation bubbles or crossflow phenomena 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 representative small scale stream-traced intake. The cross-flow was not anticipated during the design process and leads to a local accumulation of decelerated fluid in the vicinity of 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.