Shock Focusing in the Interaction with a Local Area of Increased Gas Density

Abstract

The interaction between a shock wave and a round area of a gas of increased density is simulated numerically by solving Euler’s equations in the two-dimensional plane and axisymmetric formulations. These formulations of the problem describe the interaction of a shock with a heavy gas cylinder or bubble, respectively. The shock refraction and focusing processes are described considering two different regimes of interaction—external and internal. It is revealed that there are three successive pressure peaks reached on the axis (plane) of symmetry both outside and inside of the shocked inhomogeneity. The dependence of the peak pressures on the initial gas density in the inhomogeneity considered is determined for two different shock Mach numbers and it is found that in the plane and axisymmetric cases the highest pressures are reached in different regimes.