Numerical Computation of Steady State Scattered Sound External to Submerged Infinite Cylinders by Combining Finite Element and Integral Equation Methods,

Abstract

In a previously reported investigation, scattered sound pressures and velocity distributions on the surfaces of submerged infinite cylinders ensonified by steady-state plane waves were calculated. The numerical method used for these calculations was based on a finite element formulation of the coupled fluid-structure interaction problem and implemented using the NASTRAN computer program. In the present investigation, these pressure and velocity data are used as the basis for numerical calculations of the scattered sound pressures generated in the exterior fields of the cylinders. The method consists of replacing an infinite cylinder by a finite cylinder whose external sound field, in three dimensions, converges to the required two-dimensional (2-D) field as the cylinder length increases. The field pressures are obtained by numerical quadrature of the HELMHOLTZ integral formulation which relates external field pressures to pressures and normal velocities at the structural surface. Calculated 2-D pressure fields, obtained for rigid and elastic cylinders, are in excellent agreement with analytical results. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1983
Accession Number
ADA134773

Entities

People

  • F. M. Henderson

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustic Propagation
  • Acoustics
  • Computer Programs
  • Computers
  • Elastic Scattering
  • Equations
  • Frequency
  • Geometry
  • Numerical Quadrature
  • Plane Waves
  • Pressure Distribution
  • Scattering
  • Sound Pressure
  • Sound Waves
  • Steady State
  • Three Dimensional
  • Two Dimensional

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Structural Dynamics.