Effects of Spanwise Structures and Unsteady Forcing of Vortex Generators on a Shock-Induced Separated Flow Using Planar Laser Scattering

摘要

Through the use of planar laser scattering, the effects of vortex generators (VGs) on the separation shock in an unswept compression ramp interaction have been investigated in a Mach 2 and Mach 5 wind funnel. Additionally, the undisturbed Mach 5 boundary layer was examined for the existence of long strips of uniform momentum fluid. These strips were previously identified in a Mach 2 boundary layer but had not been observed at Mach 5. The effects of the strips on the Mach 5 compression ramp interaction were also investigated. The counter-rotating vane-type VGs used in this study moved the shock downstream and reduced the separation region at both Mach 2 and Mach 5 however, at Mach 5 the control was sporadic and did not move the shock beyond the extent of the intermittent region. The reduced effectiveness at Mach 5 may be a result of the VGs rising to a significantly lower scaled height. This was necessary because the VGs resulted in large-scale separation when inserted farther into the boundary layer. Plan view PLS imaging in the streamwise-spanwise plans showed the VGs created a highly three-dimensional separation region in both the Mach 2 and Mach 5 interactions.