Numerical study on the evolution of the shock-accelerated SF6 interface: Influence of the interface shape

Abstract

The early phases of the shock interaction process on two-dimensional interfaces with different shapes are numerically investigated in this study, which are closely related to the shock refraction and reflection, vorticity production and transport. The numerical method employs an adaptive unstructured quadrilateral mesh, which can capture the wave pattern and interface evolution very well. Simulations are carried out under the conditions of an incident shock Mach number of 1.2 and the light/heavy (air/SF6) interface. Five different shapes are considered in the simulations: rectangle, ellipse, diamond and two kinds of triangle. The results show that the interfacial shapes can influence the wave patterns particularly on the shape and evolution of refracted shock waves. The generation and the distribution of vorticity on the interfaces with five different shapes also have dissimilarities. The circulation deposition on five interfaces is quantitatively investigated and compared with theoretical model. A good agreement is found between the numerical results and the predictions by the theoretical model. Some characteristic scales of the interface are tracked. Under the influence of nonlinear-acoustic effect and vorticity effect, the interfaces present different evolution modes.