Boundary-layer transition on swept cylinders at hypersonic speeds

摘要: We present boundary-layer transition data on swept cylinders in hypersonic flow that were obtained the Ludwieg-tube wind tunnel of DLR. Experiments conducted at M∞ = 5.0 and 6.9 for three with without end plates sweep angles 30, 45, 60 deg, respectively. To determine state boundary layers, liquid-crystal technique was applied. In addition, response attachment-line to surface roughness heights due trip wires 45 deg investigated. Freestream Reynolds numbers based cylinder diameter about 0.2-0.3 x 10 6 plate disturbances 0.9-1.2 no contaminations. Trends are roughly similar subsonic ones respect critical heights. The behavior around heights, however, depended strongly spanwise Mach numbers. With visualizations, off-attachment-line could be observed, as well fine streak pattern laminar region upstream front, confirming streamwise vortices induced by crossflow instability speeds.