Interactions between shock wave and hypersonic laminar boundary layer near convex corner

Abstract

A hypersonic gun tunnel was used to investigate a Mach 8 laminar boundary layer interacting with an externally generated shock wave impinging in the neighborhood of a convex corner. Surface static pressure measurements and schlieren photographs were taken from planar models with corner angles of 5 and 10 deg;the shock generator was set to the same angles. The results are compared with data obtained in the same tunnel for an externally generated shock impinging on a flat-plate boundary layer, and for a boundary layer interacting with a cornerexpansion wave. When separation and reattachment both occur either upstream or downstream of the corner, the 5- and 10-deg interactions have similar properties; however, they differ markedly when separation is upstream and reattachment is downstream. The results also suggest that a convex corner will not completely suppress separation caused by an externally generated shock, even when impingement is close to the corner. However, the extent of separation is minimized when the separation point is located at the corner, corresponding to shock impingement 2-4 boundary-layer thicknesses downstream of the corner. Nevertheless, the overall interaction length still extends over many boundary-layer thicknesses.