High sampling-rate measurement of turbulence velocity fluctuations in Mach 1.8 Laval jet using interferometric Rayleigh scattering**Project supported by the National Natural Science Foundation of China (Grant No. 11272337).

Abstract

Interferometric Rayleigh scattering diagnostic technique for the time-resolved measurement of flow velocity is studied. Theoretically, this systematic velocity-measured accuracy can reach up to 1.23 m/s. Measurement accuracy is then evaluated by comparing with hot wire anemometry results. Moreover, the distributions of velocity and turbulence intensity in a supersonic free jet from a Laval nozzle with a Mach number of 1.8 are also obtained quantitatively. The sampling rate in this measurement is determined to be approximately 10 kHz.