Experimental and numerical study on instability structure of the supersonic mixing layer (Mc=0.5)

摘要

The parameters of instability wave of supersonic mixing layer (Mc=0.5,M1=3.5/M2=1.4) are measured by flow visualization and calculated by means of two-dimensional direct numerical simulaitons of the compressible Navier-Stokes equations.In both cases of the mixing layer with harmonic disturbance or not,the comparative results indicate that the wavelength of the two-dimensional wave is equal to the vortex spacing in the streamwise direction because the difference between them is less than 1%.However,the measured convective velocity of the large-scale structure deviates from the theoretical isentropic prediction about 10%.Here the measured value confirms that Mc,2＜Mc,1 for the supersonicsupersonic mixing layer.Furthermore,the pairing and intermittent phenomenon are recorded clearly by flow visualization.