Simultaneous density and velocity measurements in a supersonic turbulent boundary layer

A novel technique for simultaneous measurements of instantaneous whole-field density and velocity fields of supersonic flows has been developed. The density measurement is performed based on the nano-tracer planar laser scattering (NPLS) technique, while the velocity measurement is carried out using particle image velocimetry (PIV). The present experimental technique has been applied to a flat-plate turbulent boundary layer at Mach 3, and the measurement accuracy of the density and velocity are discussed. Based on this new technique, the Reynolds stress distributions were also obtained, demonstrating that this is an effective means for measuring Reynolds stresses under compressible conditions.