Vortical regime of the flow behind the bow shock wave

A new nonstationary regime of the flow around a step and a cylinder was found to exist at high free-stream Mach numbers for gas specific heat ratios below 1.2. The main features of the flow are strong vortices in the shock-compressed region with supersonic reversal velocities at the body face. The bow shock wave takes on a complicated shape, fluctuating in time. The vortical regimes can result from local heterogeneities in the free stream. The case of the heterogeneity is studied in this paper in the form of a thin thermal layer of limited length. The vortical regime remains in existence after the source of disturbances is removed. The results have been obtained through computer simulations through the use of Eulerian hydrodynamic equations and by way of several numerical methods: FLIC, Godunov's scheme, TVD, and PPM. The influence of viscosity on the development of the vortical regime has been studied by computer solving the Navier–Stokes equations. Received 21 August 1998 / Accepted 6 June 2001