Experimental Investigation of Mechanical Distortions to Hypersonic Boundary Layers

Destabilization of the boundary layer in hypervelocity flight can significantly increase the surface heat flux. For example, a stretch of concave surface curvature has been found to increase the skin friction by 125 % [1]. Goertler vortices were found to cause fluctuations in heat transfer of 20-30% in a Mach 7.1 flow over a concave compression ramp [2]. Ekoto et al. carried out an extensive study of global (adverse, favorable, and combined pressure gradients) and local (due to surface roughness) distortions in a turbulent hypersonic boundary layer [3]. Building on these works, we experimentally investigate the structure and breakdown of imposed vortex structures in a laminar hypervelocity boundary layer over a flat plate, and linear and curved compression surfaces