Hypersonic boundary layer transition visualization in CARDC hypervelocity ballistic range

Hypersonic boundary layer transition measurements were conducted in the ballistic range of CARDC. The models were 7° half angle cones, made of aluminum alloy, with black oxidation or low thermal conductivity coating. Techniques of pulse laser lighted shadowgraph and inferred thermography were adapted in the experiments and typical results under Mach number 4.89 and 6.27 were obtained. The shadowgraph images show boundary layer flow structures and phenomena, including the laminar, transition and full developed turbulence. Based on FFT analysis of the shadowgraph image, a quantitative starting point of the transition can be calculated. For the inferred method, a half of the cone model can be imaged and the boundary where transition occurs can be observed. The results of the two measurement methods are basically consistent with each other.