| Abstract: | The method of 2] is used to examine the interaction of a shock or an expansion wave in the outer plane supersonic stream with a turbulent near wake. It is shown that the flow in the disturbed near wake may be two-valued, and for fixed conditions in the outer stream quasisteady transitional flows between these two steady states are possible. Under the influence of some external disturbing mechanism (believed to be turbulent pulsations of the large-vortex type) these quasi-steady flows become relaxation oscillations which lead to the experimentally observed base-pressure oscillations.The theoretical conclusions are confirmed by an experimental study of the base-pressure fluctuations which develop in a two-dimensional expansion-deflection nozzle with interaction of the off-design shock with the near wake.In conclusion the author wishes to thank G. G. Chernyi and G. N. Abramovich for helpful discussions of the study and L. V. Kapranova, T. S. Soboleva, and Z. A. Donskova for assistance in performing the calculations. |
