Free Flight Experiment Investigation of AOA Effect on Cone Boundary Layer Transition at Mach 6

Abstract

To investigate the angle of attack (AOA) effect of hypersonic boundary layer transition on slightly blunted cone, China Aerodynamics Research and Development Center has conducted a series of ballistic free flight experiments on 5° half angle circular cones. The projectile is 110 mm long with surface roughness between 0.46 μm and 0.77 μm. Six shots were taken under Mach 6 and separated unit Reynolds numbers, and the AOA varied between 0.2° and 7.9°. Results showed that the transition shifted upward to the nose tip on the leeside and afterward to the bottom on the windside within small AOA of less than 3°. When the angle got further increased, the moving direction of the transition on the windside reversed toward the nose tip but will not exceed the leeside in present results with nose tip radius of less than 0.4 mm. The transition Reynolds number without AOA was about 4.7 × 106, and there was a noticeable decrement with AOA, which may relate with both pressure gradient and wall heating difference.