New visions in experimental investigations of a supersonic under-expanded jet into a high subsonic crossflow

Abstract

A series of experiments was performed to investigate the interaction of an under-expanded axisymmetric supersonic jet exhausted from a flat plate with a high subsonic crossflow. The goal was to study the effect of boundary layer thickness (δ) and jet to freestream dynamic pressure ratio ( J) on flow field pressure distributions. The resulting measurements upstream of the jet showed that with increasing boundary layer thickness, the magnitude of the pressure coefficient decreases, whereas downstream of the jet, the recovery of the back-pressure moved closer to the nozzle exit. Flow field measurements indicated that with increasing boundary layer thickness, the jet plume dissipation rate increased, whereas the strength of the counter-rotating vortex pair (CRVP) did not vary significantly. In addition, it was clearly observed that with increasing J, the CRVP penetrated into the crossflow and the magnitude of the pressure coefficient on the surface upstream and downstream of the jet increased.