SHOCK-FREE CONICAL COMPRESSION AND EXPANSION OF A GAS

Solutions of two-dimensional unsteady self-similar problems of the unl imited shock-free compression and expansion of an ideal gas into a vac uum when the gas is at rest at the initial instant of time inside a pr ism and cone-shaped bodies at constant density and pressure are constr ucted. The flow fields are partially constructed using classes of accu rate solutions of the non-linear equation for the velocity potential, and partially by numerical calculations, in particular, by the method of characteristics. The features of the formulation of the boundary-va lue problems for conical unsteady flows are investigated. Approximate laws of the control of the motion of compressing pistons are construct ed analytically. The degrees of cumulation of energy and density are o btained and it is shown that the non-uniform compression processes des cribed are more favourable energy-wise than the process of spherical c ompression for obtaining local superhigh densities of a material. The flow fronts with points of discontinuity are constructed for problems of flow into a vacuum from a cone.