PIV study of supersonic flow around an optical bow cap

Velocity field of supersonic optical bow cap was studied using PIV (Particle Image Velocimetry) in Ma =3.8 supersonic wind tunnel. The application of PIV to supersonic flow de-mands good performance of PIV hardware, fine flow-following ability of tracer particle and high accuracy of PIV algorithms.Synchronizer with high accuracy and high energy laser were chosen for the PIV system in this paper; tracer particle with diameter at nanometer scale was selected and its performance in supersonic flow was assessed through measurements of particle lag down-stream of a two-dimensional oblique shock wave; several high-accuracy PIV algorithms were used for particle image processing.The results revealed that the tracer particle performed very well in supersonic flow, and the algorithms yielded the velocity field of the supersonic optical bow cap faithfully.