Accession Number : ADA294441

Title :   Interactions of a Target with its Acoustic Environment.

Descriptive Note : Final rept.,

Corporate Author : NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

Personal Author(s) : McDaid, E. P. ; Gillette, D. ; Barach, D.

PDF Url : ADA294441

Report Date : SEP 1994

Pagination or Media Count : 58

Abstract : The results of a project to develop the capability to numerically model the sound scattered from a target in a dispersive environment are reported. The target has been rigorously coupled to its environment by combining a finite element formulation of the target shell dynamics with a Helmholtz Integral Equation formulation of fluid loading and a normal mode formulation of sound propagation. Though the computational cost of obtaining numerical solutions to this problem are awesome, some simple approximations can result in significant savings. In particular, neglect of Fresnel diffraction and boundary-induced multiple scattering permits a particularly simple and tractable reformulation of the problem. The reported work makes the following contribution to solving the problem of target-environment interactions: the errors caused by neglecting Fresnel diffraction terms and multiple scattering are numerically evaluated. (AN)

Descriptors :   *ACOUSTIC SCATTERING, *SONAR, *ANTISUBMARINE WARFARE, MATHEMATICAL MODELS, COMPUTATIONS, FINITE ELEMENT ANALYSIS, ELASTIC PROPERTIES, BOUNDARIES, SOLUTIONS(GENERAL), DIFFRACTION, APPROXIMATION(MATHEMATICS), SOUND TRANSMISSION, DIFFERENTIAL EQUATIONS, NUMERICAL METHODS AND PROCEDURES, INTEGRAL EQUATIONS, UNDERWATER ACOUSTICS, ACOUSTIC VELOCITY, OCEAN ENVIRONMENTS, SONAR SIGNALS, TARGET STRENGTH, FORMULAS(MATHEMATICS), DISPERSIONS, UNDERWATER TARGETS, FRESNEL INTEGRALS.

Subject Categories : Acoustic Detection and Detectors
      Undersea and Antisubmarine Warfare

Distribution Statement : APPROVED FOR PUBLIC RELEASE