The Construction of Shell Theories with Fluid Loading to Approximate Scattering from Submerged Bounded Objects Via Techniques in a Differential Geometry

Abstract

One can predict sound scattering from fluid loaded elastic shells based on exact elastodynamic theory provided the shell is a sphere or an infinite cylinder or some other geometry for which the elastodynamic equations are separable. Problems arise for more general shapes with only limited success for spheroids and cylinders with hemispherical end caps using the Extended Boundary Condition (EBC) method of Waterman. Both Radlinsky and the Varadans have employed a marriage of the EBC method with shell theories with some progress being made in the description of the scattering event. With this in mind, our objective is to extend the progress made by the above researchers by employing more physical shell theories. It is usual to construct shell theories via use of geometrical constructions, or by use of variational principles. In this study we explore the use of principles from differential geometry to construct appropriate theories that include translational motion and rotary inertia, as well as effects due to fluid loading. Some common thin shell theories which are employed for spherical elastic shells are deduced from these general terms and are compared to exact theory for verification as well as a test of limitations.... Acoustic scattering, Shallow water, Waveguide propagation.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1993
Accession Number
ADA260599

Entities

People

  • Cleon E. Dean
  • Michael F. Werby

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Impedance
  • Acoustic Scattering
  • Acoustics
  • Differential Equations
  • Differential Geometry
  • Elastic Shells
  • Energy
  • Equations
  • Equations Of Motion
  • Frequency
  • Geometry
  • Kinetic Energy
  • Military Research
  • Phase Velocity
  • Potential Energy
  • Resonance
  • Waves

Readers

  • Calculus or Mathematical Analysis
  • Structural Dynamics.
  • Systems Analysis and Design