Detonation of a combustible gas mixture during the interaction of a shock wave with an elliptical region of a heavy inert gas

In this paper, we numerically simulate the interaction of a shock wave in a combustible gas with an elliptical bubble of an inert gas with an increased density in a plane two-dimensional formulation using the Euler equations. The Godunov-type finite volume method of the second-order approximation is applied. Gas combustion is modeled using the two-stage Korobeinikov–Levin kinetics. Various values of the Mach number of the incident wave and the elongation degree of the inert bubble are considered, and the refraction and focusing of the incident wave are described. Qualitatively different modes of gas detonation initiation, including direct initiation by a strong wave, ignition upon reflection of a wave of medium intensity from the gas boundary, and upon focusing of secondary shock waves at lower Mach numbers of the wave are found. The dependence of the ignition mode on the wave intensity and the bubble shape is determined.