Investigation of an oblique shock wave/laminar boundary layer interaction using Laser Doppler Velocimetry (LDV)

The wholly laminar boundary layer separation associated with an incident shock wave was studied in a wind tunnel at Mach 2.20. Mean velocity profiles in and around the separation are measured using a laser Doppler velocimeter with Bragg cell. Reversed flow velocities of up to 4.2% of free stream and measurements to within 0.1 mm from the surface are obtained. Linear extrapolations of the zero-line velocities coincide with separation and reattachment points estimated from shadowgraph visualization. The measured flow field is shown to be free of large finite end effects by assessing model surface pressures with and without side plates installed. A limiting two-dimensional pressure distribution on center line is observed only when the distances between side plates exceeds more than twice that observed in comparable compression corner experiments. Velocity and surface pressure data compare very favorably with computational results obtained from a full two-dimensional Navier-Stokes code and with other experimental results.