ON THE PROBLEM OF USING PARTICLE IMAGE VELOCIMETRY FOR MEASUREMENTS IN HIGH-VELOCITY THIN SHEAR LAYERS

The flow velocity in the region of shock wave–boundary layer interaction on a plate for a Mach number M = 1.43 was measured using particle image velocimetry. The laminar and turbulent states of the incoming boundary layer are considered; the boundary-layer thickness can be two orders of magnitude smaller than the characteristic longitudinal scale of the flow. The results of measuring the boundary-layer velocity by particle image velocimetry for various equipment settings are compared with the results of measurements using various algorithms to determine tracer particle displacements and use them to reconstruct velocity fields. It is shown that the main limitation for increasing the spatial resolution is the inertia of tracer particles.