A possible mechanism of self-oscillations in flows with shock waves and contact discontinuities is studied. Flows are investigated in the heliosphere, near a blunt cone in an inhomogeneous stream, and in the vicinity of a blunt cylinder with an outflowing supersonic jet, which is supposed to be, according to this mechanism, of a self-oscillatory nature. Two-dimensional Reynolds equations with algebraic turbulent viscosity are solved by the implicit third order Runge-Kutta scheme. The results of numerical studies are presented.