Numerical Simulations of Self-Oscillatory Flows near Blunted Bodies, Giving off Opposite Jets

Abstract

New self-oscillatory compressible flows are found and investigated. Self-oscillations are supposed to be produced as a result of resonance interactions of flow "active" elements, namely, elements, amplifying disturbances. Hypothesis is used that contact discontinuities and intersection points of shocks with shocks or shocks with contact discontinuities compose the flow set of "active" elements. Two-dimensional Reynolds-averaged Navier-Stocks equations added by an algebraic turbulence model are solved by an implicit third order Runge-Kutta scheme. Well studied open cavity flow and jet impinging on a plane are calculated to verify the numerical method and the turbulence model. Compressible flows near blunted bodies, giving off supersonic opposite jets from forehead surfaces, are discovered to have self-oscillatory regimes.

Sonic Underexpanded Jet Impinging on the pair open tube – inner cylinder

“…Numerical search for new self-oscillatory compressible flows, started in [1,[17][18], is continued in recent paper. Sonic underexpanded jet impinging on cylindrical bodies, placed in open tubes, is found to have self-oscillatory nearly periodic regimes.…”