Accession Number:

ADA230004

Title:

Analysis of Thickness 'Resonances' When Scattering from Submerged Elastic Shells at High Frequency

Descriptive Note:

Abstract

Corporate Author:

NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS

Personal Author(s):

Report Date:

1990-01-01

Pagination or Media Count:

1.0

Abstract:

When sound scatters from an elastic spherical shell submerged in water at suitably high frequencies, it is noted that backscattered returns, when plotted as a function of frequency, display unusually large signals over a broad frequency, display unusually large signals over a broad frequency range. The point at which this occurs is a function of both shell thickness and material properties. The effect is illustrated for five elastic materials and three shell thicknesses 15 distinct examples. Simple expressions that predict the location of the strong returns in ka the ka values, where k is the wave number in the fluid and a is the radius of the sphere for all 15 examples are then given. The results are also examined in partial wave space and are explained within the context of flexural waves and half-integral wavelengths that correspond to the thickness of the sphere.

Subject Categories:

  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE