Interior and Exterior Resonances in Acoustic Scattering. I. Spherical Targets II. Targets of Arbitrary Shape (T-Matrix Approach).
Abstract
SPHERICAL TARGETS. In acoustic scattering from elastic objects, resonances features appear in the returned echo at frequencies where the objects eigenfrequencies are located, which are explained by the excitation of interior creeping waves. Corresponding resonance terms may be split off from the total scattering amplitude, leaving behind an apparently nonresonant background amplitude. This is demonstrated here for scatterers of spherical geometry, and in the following companion paper also for scatterers or arbitrary geometry, using the T-matrix approach. For the case of near-impenetrable spheres, it is subsequently shown that the background amplitude can be split further into specularly reflected contributions, plus highly attenuated resonance terms which are explained by the excitation of exterior (Franz-type) creeping waves. The singularity structure of the scattering function is shown mathematically, using the R-matrix approach of Nuclear scattering theory, as that of a meromorphic function without any additional 'entire function' (as had been postulated by the Singularity Expansion Method). (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 14, 1981
- Accession Number
- ADA105534
Entities
People
- D. Brill
- E. Tanglis
- G. C. Gaunaurd
- H. Ueberall
Organizations
- The Catholic University of America