Scattering and Radiation of High Frequency Sound in Water by Elastic Objects, Particle Suspensions, and Curved Surfaces
Abstract
Research in the following areas is reported: (A) Scattering of high- frequency sound by elastic objects in water--Experiments and theory are examined mostly for problems not describable by thin shell theory including: backwards- wave high-frequency enhancement of backscattering by shells; coincidence frequency enhancement for chirped bursts and impulses; a novel impulse generator and the effect of the mass-per-area of the shell on the specular return; and the application of time-frequency analysis. Some leaky wave scattering properties are examined including the Fresnel width of the coupling region, a convolution formulation, and a variable phase coupling coefficient. Retro-reflective backscattering of sound due to Rayleigh waves on objects with corners is demonstrated. (B) Radiation mechanisms for fluid-loaded plates--A flexural wavepacket is launched to propagate down a plate that has only its bottom half submerged. When the packet crosses the free surface of the water, there is a burst of acoustic radiation into the water due to the jump in fluid loading. This transition radiation is measured and modeled. (C) Caustic wavefields and diffraction catastrophes--Echo fluctuations associated with caustics in wavefields produced by reflection from rough surfaces and optical observations of E6 diffraction catastrophes. (D) Interaction of sound with sound mediated by a suspension.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 27, 1994
- Accession Number
- ADA283093
Entities
People
- Philip L Marston
Organizations
- Washington State University