Experimental study of overall roughness surface effect on hypersonic boundary layer transition of yawed cone

Crossflow instability will be present when the vehicle has an angle of attack in hypersonic flow, and it might play a dominant role in hypersonic boundary layer transition. By far the mechanism of crossflow instability-induced hypersonic boundary layer transition is still out of understanding, although the large effort has been devoted. Upon this work, the overall roughness effect on instabilities in hypersonic flow was researched experimentally. Surface flush-mounted pressure sensors and infrared camera were employed to investigate the instability waves when different rough surfaces were deployed. The results reveal that the moderate surface roughness level on cone model can suppress the growth of crossflow instabilities at certain azimuthal angles in hypersonic flow.