Accession Number : ADA309628

Title :   Numerical Methods for Underwater Structural Acoustics.

Descriptive Note : Final rept. 1 Mar 94-30 Jun 95,

Corporate Author : MARYLAND UNIV COLLEGE PARK OFFICE OF RESEARCH ADMINISTRATION AND ADVANCEMENT

Personal Author(s) : Elman, Howard ; O'Leary, Dianne P. ; Saltz, Joel ; Stewart, G. W.

PDF Url : ADA309628

Report Date : 30 JUN 1995

Pagination or Media Count : 5

Abstract : This report represents the status of the project referenced above as of June 30, 1995, the conclusion of the term of this grant. The project centered on a problem in structural acoustics: to determine the reflection properties of an underwater object interacting with sonar signals. To generate representative problems, we have been using the SARA package produced by H. Allilk and D. Moore of Bolt Beranek and Newman, New London. CT. This code uses a finite/infinite (quadratic) element formulation in the frequency domain. The resulting; linear system, which is complex symmetric, is currently solved with heavy dependence on; secondary storage (i.e., disk) by Gaussian elimination using a frontal approach with no pivoting for stability. This method has given adequate numerical results, even though it might be expected to fail due to resonances in the system. It is also likely to be too costly to handle large problems, especially for three dimensional models. Our goal has been to investigate two alternative approaches that we expect will alleviate these difficulties: the use of iterative methods and the use of parallel sparse solvers.

Descriptors :   *NUMERICAL METHODS AND PROCEDURES, *UNDERWATER ACOUSTICS, *SONAR SIGNALS, MATHEMATICAL MODELS, ALGORITHMS, LINEAR SYSTEMS, OPTIMIZATION, MATRICES(MATHEMATICS), FINITE ELEMENT ANALYSIS, ELASTIC PROPERTIES, PARALLEL PROCESSING, ITERATIONS, FREQUENCY DOMAIN, UNDERWATER STRUCTURES, ACOUSTIC REFLECTION, ACOUSTIC RESONANCE, UNDERWATER OBJECTS.

Subject Categories : Operations Research
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE