MECHANISMS UNDERLYING TRANSITIONAL AND TURBULENT BOUNDARY-LAYER (TBL)FLOW-INDUCED NOISE IN UNDERWATER ACOUSTICS (II)

This research applies dynamical system methods (i.e., Chaos Theory) to the processing of time sequences of transitional and turbulent wall-p ressures impinging on the face of station probes mounted along the wal l of an axisymmetric body of revolution during a buoyant ascent from t he bottom of a deep water test basin. It is demonstrated that the turb ulent pressure fluctuations for this experiment can be described as a dynamical system of sufficiently low order (i.e., less than ten degree s of freedom). This opens up several possibilities for the control of turbulence. In underwater acoustics this translates to flow noise redu ction in sonar applications and to drag reduction in ship dynamics. Ot her potential commercial applications include control of flow through pipelines and aerodynamic design.