Evolution of the diffusion mixing layer of two gases upon interaction with shock waves

A mathematical model of mechanics of a two-velocity two-temperature mixture of gases is developed. Based on this model, evolution of the mixing layer of two gases with different densities under the action of shock and compression waves is considered by methods of mathematical simulation in the one-dimensional unsteady approximation. In the asymptotic approximation of the full model, a solution of an initial-boundary problem is obtained, which describes the formation of a diffusion layer between two gases. Problems of interaction of shock and compression waves with the diffusion layer are solved numerically in the full formulation. It is shown that the layer is compressed as the shock wave traverses it; the magnitude of compression depends on shock-wave intensity. As the shock wave passes from the heavy gas to the light gas, the mixing layer becomes overcompressed and expands after shock-wave transition. The wave pattern of the flow is described in detail. The calculated evolution of the mixing-layer width is in good agreement with experimental data.