Numerical study on shock-accelerated heavy gas cylinders with diffusive interfaces

Interactions of shock waves and heavy gas cylinders with different diffusive interfaces are numerically investigated. Comparisons among these interfaces are made in terms of cylinder morphology, wave system evolution, fluid mixing, and circulation generation. Navier–Stokes equations are solved in the present work to simulate the complex multi-fluid flow. A fifth-order weighted essentially non-oscillatory scheme is used to compute the numerical flux. The influence of interface diffusion is revealed by numerical results. Cylinders with similar geometric scale but different diffusion interface have significant similarities in hydrodynamic characteristics, including the interface morphology, shock focusing, and molecular mixing, as well as circulation deposition. For cases with more severe interface diffusion, the cylinder develops into more regular vortex pairs. The diffusive interface significantly mitigates the strength of the reflected shock wave and weakens the shock focusing capability. Some interface evolution features are also recorded and analyzed. The diffusive interface brings about slower molecular mixing and less circulation generation. The circulation deposition on different interfaces is quantitatively investigated and compared with the theoretical models. The theoretical models are found to be applicable to the scenarios of diffusive interfaces.