Theory for the Propagation of Undulating Disturbances Upstream in a Subsonic Free Jet,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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Experimental observations have shown that a periodic pressure disturbance inside a subsonic jet propagates upstream in a way that may be explained as waves traveling obliquely to a jet axis, which are totally reflected at the jet boundary layer. This pressure wave induces axisymmetric ring vortices in the free boundary near the nozzle exit, which intensifies the noise of the jet considerably. A good agreement between the solutions for a clear model representation and the results of the theoretical computation of the propagation of undulating disturbances traveling upstream is found. Outside the jet a near field is induced, and its decrease perpendicular to the jet is computed.
- Fluid Mechanics