Large-scale unsteadiness in a compressible, turbulent reattaching shear layer

Abstract

The large-scale unsteadiness that occurs in shock-wave/boundary layer interactions imposes severe aero-thermo-acoustic loads on high-speed aircraft. Much progress has been made on this problem in the last two decades: these interactions can now be tackled with large eddy simulation, at least for relatively low Reynolds numbers. Further, a large body of evidence now suggests that the physical mechanism for the unsteadiness lies in the selective amplification, within the separated flow, of large-scale disturbances originating in the incoming turbulent flow. The present paper examines the kinematics of these incoming structures in a turbulent boundary layer, and the scaling of the corresponding response of a reattaching shear layer flow. In particular, it presents an overview of the influence on recent research of experimental work carried out by Smits’ group at Princeton University in the 1990s.