LIMITATION OF CUMULATION AND GENERATION OF VORTEX STRUCTURES IN CONVERGING SHOCK WAVE WITH BROKEN SYMMETRY

Abstract

Calculations of a vortex structure formation in the vicinity of the focus of a perturbed converging shock wave were performed, based on the compressible Euler equations in the framework of 2D formulation. The low-mode perturbation leading to limited cumulation is considered. At the stage of the converging shock wave, the latter is a source of flow vorticity, the intensity of which increases with decreasing distance to the focus according to a power law. The formation of the most intense vortices is observed on the scale of the transition from the Mach to the proper (regular) interaction of segments of the converging shock wave. It is shown that the presence, along with the second mode, of intermediate unstable modes leads to the intensification of mixing of high-entropy gas in the vicinity of the shock wave focus. In the presence of only the second mode, the hot high-entropy gas is concentrated in the cores of two vortex pairs formed as a result of the interaction of two converging jets. For the first time, it is shown that a small perturbation by shear in the plane of symmetry on the generation scale leads to asymmetric flow swirl on the scale of the cessation of cumulation.