Experimental Investigations of Supersonic Turbulent Flow over a Compression Ramp

Experimental studies of supersonic flow over a 28° compression ramp were carried out in a Mach 3.0 wind tunnel; the incoming boundary layer was turbulent flow. Fine flow structures were visualized via NPLS (nano-tracer-based planar laser scattering) technique. Analysis of two NPLS images between 10 μs revealed the spatio-temporal evolutions of flow field. The angles of separation shock and reattachment shock, and the development of boundary layer after reattachment were measured by time-averaged flow field. Velocity field structures were measured using particle image velocimetry technique. Streamlines in the mean velocity field indicated reverse flow in separation region, and variations of velocity vectors showed velocity shear. Moreover, flow separation and reattachment were clearly revealed by the analysis of velocity field.