Instability of Subsonic Gas Flow Near Confined Area of Heat Release

A problem of a subsonic flow around a cylindrical area of the hot gas or low-temperature plasma with a transversal stream of the viscous heat-conducting gas is considered. The cylindrical area size is fixed in time and space. The free flow speed is essentially subsonic, so a process develops at a practically constant (atmospheric) pressure. Temperature inside the heat release area reaches 2000...15000 K, so ratio between gas densities inside and outside the heat release area is 8...90, i.e. the free gas stream in reality flows around the area with essentially lower density. Various regimes of the gas flow around the confined area of heat release, including conditions of initiation of the gas flow self-pulsations, are found using a numerical approach. Obtained data allows explaining the deduced from experiments fact of initiation of the gas flow self-pulsations in the vicinity of laser burning-waves used for creating laser-plasma accelerators and laser rocket engines.