Measurement of nonlinear wave coupling and energy transfer in planar jet shear layer transition
Abstract
An experimental investigation of the nonlinear spectral dynamics involved in the transition of an initially laminar planar jet shear layer at moderate Reynolds number is presented. Application of a novel measurement technique allows the linear and nonlinear wave coupling coefficients which characterize the local spectral dynamics to be estimated from digitized time-series fluctuation data. From the linear coupling coefficient, the dispersion relation and spatial growth rate may be obtained. The magnitude of the nonlinear coupling coefficient provides a measure of the local efficiency of nonlinear three wave coupling. A related nonlinear power transfer function is also determined which provides a graphic view of the direction of the local spectral energy transfer that characterizes the transition process. When used in conjunction with the local quadratic bicoherency and the linear-quadratic coupling bicoherency, the local nonlinear spectral dynamics of the flow may be completely and unambiguously quantified.
- Publication:
-
29th AIAA Aerospace Sciences Meeting
- Pub Date:
- January 1991
- Bibcode:
- 1991aiaa.meetS....T
- Keywords:
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- Flow Theory;
- Jet Flow;
- Laminar Flow;
- Shear Layers;
- Transition Flow;
- Wave Interaction;
- Fourier Transformation;
- Reynolds Number;
- Transfer Functions;
- Fluid Mechanics and Heat Transfer