Supersonic laminar boundary layer separation near a compression corner

Abstract

Detailed measurements were performed in the region of interaction of a laminar boundary layer with a compression corner at Mach numbers near 2.5. Different models were tested permitting variation in the angle of compression and the conditions downstream of reattachment. The heat flux and the resistance of equilibrium of a hot wire anemometer at any location in the flow field were measured. These measurements were supplemented by either the wall or the pi tot pressure to compute all thermodynamic and dynamic variables. The results permitted verification of the hypothesis of zero normal pressure gradients when the compression angle is small and the boundary layer is laminar. The enthalpy in the separated bubble was constant and equal to the wall enthalpy of a flat plate with attached laminar boundary layer at the same Mach number. Evidence of a reversed flow with velocities approximately 5% of the free stream velocity was observed. The recompression along the separating streamline was found to be very nearly isentropic. Critical points were located in the reattachment region and a physical explanation proposed with special emphasis on the location of transition.