ACOUSTIC RADIATION FROM SUBMERGED ELASTIC STRUCTURES

Authors
  1. Brennan, D.P.
  2. Chernuka, M.W.
  3. Norwood, M.E.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);MARTEC Ltd, Halifax NS (CAN)
Abstract
The report describes the program, AVAST, which utilizes an iterative technique to predict the acoustic radiation characteristics of an elastic three-dimensional structure, vibrating in either an infinite or half-space fluid medium. AVAST combines the use of the finite element method for the structure with the boundary element technique for the fluid. The finite element method is used to define the mechanical mobility matrix relationship between excitation forces (in a particular direction and at a particular frequency) and structural velocities at fluid-structure interface nodes. The boundary integral technique is used to generate a system of equations relating surface velocities to fluid acoustic pressures. The surface pressures, initially unknown, are first approximated using a plane wave impedance condition. This satisfies the mobility relationship requirements and provides a reasonable estimate for the surface velocities which are then used as boundary conditions for the discrete forms of the Helmholtz integral exterior equations. These result in a unique set of surface pressures which can be compared to those provided by the plane wave idealization. If the pressures are not within some predetermined convergence criteria, these updated pressures are used to compute a new set of surface velocities and the process is repeated until convergence is attained. TRUNCATED.
Report Number
DREA-CR-93-431;MARTEC-TR-92-11 — Contractor Report; Technical Report
Date of publication
01 Jun 1992
Number of Pages
73
DSTKIM No
93-04609
CANDIS No
134929
Format(s):
Hardcopy;Originator's fiche received by DSIS

Permanent link

Document 1 of 1

Date modified: