The shock-vortex interaction: The origins of the acoustic wave

Abstract

In this paper we discuss the mechanisms responsible for the formation of the acoustic wave when a shock interacts with a vortex. Experimental measurements have shown that this interaction produces a primarily quadrupolar acoustic wave with a strong compression attached to the shock front. We review earlier work which shows that this strong compression is due to the distortion of the shock. The origin of the quadrupolar component is examined by comparing twodimensional computations of the shock-vortex interaction to those of an isolated elliptical vortex. The elliptical vortex is similar to the compressed vortex produced when a shock interacts with an initially circular vortex. We concentrate on interactions in which the shock transit time is short. The pressure field of the shock-vortex interaction is compared to that of an analogous isolated elliptical vortex for three cases: a weak shock interacting with a weak vortex, a strong shock interacting with a weak vortex, and a strong shock interacting with a strong vortex. Our results indicate that both shock distortion and vortex compression are important to the formation of the acoustic wave.

Multistage interaction of a shock wave and a strong vortex

“…The deformation of the incident shock wave in the interaction of a shock wave and a single vortex is very important and has been extensively studied in the literature. [12][13][14]18,19,21 Most of the previous studies focused on the interaction of a shock wave and weak vortices. The reflected shock wave is weak and cannot interact with the deformed vortex.…”

“…It has been studied extensively. 2,[4][5][6][12][13][14]18,19,[21][22][23]25,27 However, for the problem of shock interacting with a strong vortex, the multistage interactions result in a different mechanism of the generation of sound waves.…”

“…The numerical result showed that the vorticity was increased and the vortex was bent according to the curvature of the shock. Ellzey et al 12 and Ellzey and Henneke 13,14 studied extensively the problem of shock-vortex interaction. The unsteady compressible Euler equations were solved using a fourth-order flux-corrected transport algorithm of Boris and Book.…”

“…In Ref. 13 the authors introduced their earlier results 17 that the shock compressed the originally circular vortex into an elliptical vortex. They studied the effect of the compressed vortex on the formation of sound waves.…”

Interaction of an oblique shock wave with a pair of parallel vortices: Shock dynamics and mechanism of sound generation

“…The interaction of a shock wave and a single vortex is one of the most simplified models of shock-turbulence interaction and has been extensively studied through experiment, [1][2][3] theoretical analysis, [4][5][6][7] and direct numerical simulation. [8][9][10][11] A brief summary of a shock-single vortex interaction is given in Zhang et al 12 In addition, Zhang et al 12 studied the interaction of a shock wave and a strong vortex. It is found that the interaction between a shock wave and a strong vortex has a multistage feature.…”