Incident impact of Mach reflection wave configuration at a planar heavy/light interface

The evolution of a planar heavy/light gas interface (SF₆/N₂) subjected to a perturbed shock wave produced by diffracting a planar incident shock over a rigid cylinder is investigated by numerical and theoretical analysis, particularly focusing on the incident impact stage of Mach reflection wave configuration. While the Mach number of incident planar shock wave is 1.8, numerical schlieren images of the Mach reflection wave over a rigid cylinder are provided, and the wave evolution during the incident impact on the heavy/light interface is quantitatively analyzed. Utilizing the three-shock theory, a theoretical solution describing the refraction process is derived, which accurately predicts the post-refraction shock wave shape, as well as the velocity perturbation and circulation deposition on the interface. Additionally, by drawing shock polar curves and rarefaction wave characteristic lines, the pressure changes and flow deflection across the wave configuration during the incident impact process are straightly described. Both the results of theoretical analysis and numerical simulation indicate that the differences in shock intensity and incident angles within the Mach reflection wave configuration lead to the velocity perturbation on the interface. And the tangential velocity caused by the shock impact results in circulation deposition on the interface. Velocity perturbation and circulation deposition dominate the early evolution of the heavy/light interface.