Flow effects in the reattachment region of supersonic laminar separated flow

Abstract

The structure of a laminar separation flow around a compression corner at a free-stream Mach number M∞ = 6 is considered. The existence of a new element in the reattachment area—a high total-pressure layer—is shown. This layer is located downstream from the reattachment line above the boundary layer, and its total pressure is higher than that in either the boundary layer beneath it or the supersonic flow above it. Its appearance is due to the difference in the total pressure losses of the streamlines passing through a compression-wave fan and a shock wave in the reattachment zone. The vortex structure in the area of attachment is considered and the formation of streamwise vortices is shown. The origin of these vortices is similar to that of Taylor–Goertler vortices in subsonic flow. The pressure-pulsation distribution in the reattachment zone is also analyzed. It is shown that the spectrum of wall-pressure pulsations in the separation zone has two local maxima, the first caused by longitudinal fluctuations in the separation region and the second by pulsations of the vortices.