Computation of acoustic scattering from elastic conical shells with endcaps using the hybrid finite element/ virtual source approach

Studying and understanding acoustic scattering pattern from underwater targets has been of interest to various communities such as the archeologists and the navy for several reasons and applications. The present state-of-the-art technique in this area involves such methods as analytical approach and FEM/BEM numerical technique. This thesis aims to study and demonstrate the power of using the hybrid virtual source/FE approach where the physical presence of a target is replaced by virtual sources placed in the vicinity of the target and in a manner where the pressure/displacement relationship on the target surface is satisfied by the virtual sources when the target is being insonified. Accurate results for the far-field radiation of the target can be obtained by superposition of the point source Green's function of each virtual source. The hybrid virtual source/FE approach shows potential to be a computationally efficient method for computing acoustic scattering. The derivation of the dynamic flexibility matrix for an elastic conical shell with endcaps will be illustrated in this thesis. It will be shown that the dynamic flexibility matrix corresponds to the acoustic admittance matrix in the virtual source approach where the scattering functions are computed in the MIT's program OASES/SCATT.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Ocean Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Low, Hwee Min Charles

Advisor dc:contributor.advisor

• Henrik Schmidt.

• Ocean Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33421

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33421