Two-dimensional self-similar flows generated by the interaction between a shock and low-density gas regions

A plane time-dependent flow generated by the interaction between a normal shock and a low-density gas region occupying a quarter of the plane is theoretically investigated. Numerical simulation is performed on the basis of the Euler equations. It is established that after the shock has come in contact with the low-density region two-dimensional self-similar flows of different type can develop. On regular interaction the original shock is refracted on the low-density region with the matching of the accelerated and original shock and the refracted contact discontinuity at a common point. On irregular interaction a complicated flow occurs; it includes curved and oblique shocks, a contact discontinuity with points of inflection, multiple matching points, a high-pressure jet, and a layered vortex. The jet and vortex structures are investigated in detail. The tendency of the gasdynamic structure development with variation in the control parameters of the problem is determined. A simplified, near-analytical technique for estimating the slopes of the main shocks and the gas parameters behind them is proposed.