Interference of stationary and non-stationary shock waves

The mathematical model of a gasdynamic discontinuity is used in the area of study concerning gas flows with large gradients of gasdynamic functions. Gasdynamic functions before and after the discontinuity meet non-linear algebraic equations called the dynamic compatibility conditions on the discontinuities. Different modes of shock wave structures forming as a result of regular or irregular interference of the incoming discontinuities of different types are described. Ranges of the initial flow parameters definition such that either shock wave structures of different modes take place or interference equations have no solutions are determined. Most attention is given to arbitrary triple shock-wave configurations. Their classification is proposed. Differential characteristics of the steady flow are studied. The notion "differential characteristics" includes first derivatives of the fundamental gasdynamic parameters with respect to natural coordinates and curvatures of the discontinuities surfaces. Effect of unsteadiness on the triple-shock configuration is examined. Some problems arising at creation of complete local theory of steady and propagating gasdynamic discontinuities interference are formulated.