Effects of disturbed transmitted shock and interface coupling on heavy gas layer evolution

Abstract

Development of a heavy gas layer with an upstream single-mode interface and a downstream planar interface accelerated by a shock wave is investigated. By considering the amplitude variation of the transmitted shock and interface coupling, a modified model is established, which provides good predictions on the linear growth rates of the perturbations on both interfaces. Through the model, the perturbation growth of the downstream interface can be frozen by choosing a suitable layer width. In such a shocked layer, interface coupling has an ignorable effect on the nonlinear evolution of the upstream interface but significantly changes the nonlinear evolution of the downstream interface. A new dimensionless approach is proposed to scale the nonlinear growth of the middle spike on the downstream interface. Finally, through modal analysis, we find that the pressure perturbations rather than interface coupling result in the formation of the small spike on the bubble head of the downstream interface.