| Abstract: | The problem of shock origination in a one-dimensional gas flow is considered in the case when the gas is subjected to external force and thermal effects on a certain section of the flow starting with the time t=0. Prior to the time t=0 the flow is stationary, and there are no external forces and energy sources. Situations are investigated for which the shock formation is associated with intersection of the characteristics from one family with the boundary characteristic separating the domain of unperturbed (stationary) flow from the nonstationary flow domain originating because of the “inclusion∝ of the external effects. This problem is particularly interesting in connection with a study of the initial stage of flow evolution in different magnetohydrodynamic apparatuses. Its solution can be used to explain and comprehend more deeply the results of numerical integration (some examples of such computations are presented in 1]) and of a “stationary∝ analysis which can be used to describe the flow for “large∝ t in a number of cases (see 2]). The analysis executed has much in common with the analysis of the question of shock origination during the advance of a piston in a gas 3] although the perturbing effect in this latter case is a surface and not a volume effect. The solution is carried out by using semicharacteristic variables, which were used in 4] in an investigation of shock formation in the piston problem in chemically reacting mixtures. |
