Linear and Nonlinear Ultrasonic Interaction on Liquid-Solid Boundaries.
Final rept. Sep 78-Sep 84,
GEORGETOWN UNIV WASHINGTON DC DEPT OF PHYSICS
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This final technical report lists tasks performed and titles and abstracts of all publications originating from a Contract during this reporting period. The experimental and theoretical work performed under this Contract was concerned with linear and nonlinear ultrasonic interactions on liquid-solid boundaries. The objectives of the project centered around the fact that propagation characteristics of water-borne ultrasonic signals are frequently explained and various calculations are done by applying a plane wave theory. This approach can, to a good approximation, explain some observed results of sound propagation, reflection, and transmission phenomena but fails to describe these effects whenever the sonic signal is confined to a bounded beam or when a solid reflector has a thickness which is comparable to the sonic wavelength or when the medium of propagation is nonlinear or when the reflecting solid is itself nonlinear, i.e., if its response to an impinging sonic signal depends on the beam width and frequency. The objective of the present project thus was the theoretical and experimental investigation of the propagation, reflection, and transmission of a bounded sonic beam in a nonlinear layered medium.