Experiments on the In fluence of a microramp array on a hypersonic shock turbulent boundary layer interaction

Experiments were performed to study the effects of an array of microramp sub-boundary layer vortex generators on a hypersonic shock/turbulent boundary layer interaction. First the interaction between the turbulent boundary layer over a smooth plate and the oblique shock wave generated at a 33° compression corner was investigated in a Mach 7.2 flow. Then two staggered rows of microramps were installed upstream of the interaction region, and the inFLuence of these vortex generators on the flow field and the separation region in particular was studied. Mean flow surveys and turbulence measurements were performed using Particle Image Velocimetry (PIV). The microramps strongly altered the flow field, decreasing the mean velocity at the spanwise locations downstream of the microramp vertices, and increasing it at the spanwise locations in between vertices. The previously two-dimensional interaction region with a large separated zone in the vicinity of the ramp corner is broken up into a three-dimensional interaction, where separation is diminished at the spanwise positions in between the microramp vertices, but increased downstream of the vertices.