Numerical study of cylindrical blast-wave propagation and reflection

The problem of an unsteady cylindrical blast-wave interaction with a flat plate is numerically investigated. The numerical simulation aims at the understanding of blast-wave propagation, reflection, and its transition phenomenon as well as the flow features induced by the blast wave. A fifth-order weighted essentially nonoscillatory scheme for spatial discretization associated with a fourth-order Runge-Kutta method for time integration is employed for solving the two-dimensional Euler/Navier-Stokes equations in a finite volume fashion. To verify the accuracy of the numerical solver developed, several problems were tested. The computed results for the test problems are shown to be accurate in comparison with experimental data. To study the flowfield of a blast wave, the problem of blast-wave propagation in a free field is explored first. Two types of initial conditions are considered. A contact-surface instability that developed around a contact surface was found in the problem with the first kind of initial condition. Next, the problem of the blast-wave interaction with the flat plate is investigated. The flow structure of a shock-shock interaction induced by the unsteady blast wave and its evolution are studied in detail. It was found that the lower the height of burst or the higher the shock Mach number, the earlier the occurrence of the transition from a regular reflection to a Mach reflection and the higher the triple points.