Calculation of the transition matrix for the scattering of acoustic waves from a thin elastic spherical shell using the COMSOL Multiphysics Finite-Element Code
| dc.contributor.advisor | Baker, Steve | |
| dc.contributor.advisor | Scandrett, Clyde L. | |
| dc.contributor.author | Ng, Kiang Chuan. | |
| dc.contributor.department | Physics (PH) | |
| dc.date | December 2011 | |
| dc.date.accessioned | 2012-08-22T15:33:08Z | |
| dc.date.available | 2012-08-22T15:33:08Z | |
| dc.date.issued | 2011-12 | |
| dc.description.abstract | In acoustics, the so-called Transition, or T-matrix relates the incident and scattered acoustic pressures of an object or scatterer. The T-matrix of a thin steel spherical shell in water has been determined by the COMSOL Multiphysics Finite-Element Code. The shell has an outer radius of 0.5m and a thickness of 1cm. It is driven at a frequency of 474 Hz such that ka=1 (where k is the acoustic wave number and a is the outer radius of the shell). A standing wave, represented by a spherical Bessel function, is incident onto the shell surface and the corresponding scattering coefficient is computed. The approach is divided into three portions. Firstly, a fluid-loaded rigid sphere is modeled using the Acoustic-Shell Interaction (ACSH) physics mode to examine the functionality of COMSOL. It also explores the degree of improvement when a refined fluid mesh is applied. Secondly, a thin spherical shell is modeled in the ACSH physics mode. This will examine the credibility of COMSOL to obtain accurate results based on thin shell approximation. Finally, a true 3D finite element, employing the 3D elastic theory, is created using the Acoustic-Structure Interaction (ACSI) physics mode. The resulting diagonal T-matrix elements achieved an accuracy of 0.1% relative to the analytical T-matrix. Ultimately, these results will be applicable to the modeling of the radiation from an arbitrarily densely-packed array of sonar transducers. | en_US |
| dc.description.service | Major, Singapore Armed Forces | en_US |
| dc.description.uri | http://archive.org/details/calculationoftra1094510661 | |
| dc.format.extent | xiv, 37 p. ; 28 cm. | en_US |
| dc.identifier.uri | https://hdl.handle.net/10945/10661 | |
| dc.publisher | Monterey, California. Naval Postgraduate School | en_US |
| dc.rights | Copyright is reserved by the copyright owner. | en_US |
| dc.subject.lcsh | Sound-waves. | en_US |
| dc.title | Calculation of the transition matrix for the scattering of acoustic waves from a thin elastic spherical shell using the COMSOL Multiphysics Finite-Element Code | en_US |
| dc.type | Thesis | |
| dspace.entity.type | Publication | |
| etd.thesisdegree.discipline | Combat Systems Technology | en_US |
| etd.thesisdegree.grantor | Naval Postgraduate School (U.S.) | en_US |
| etd.thesisdegree.level | Masters | en_US |
| etd.thesisdegree.name | Master of Science in Combat Systems Technology | en_US |
| relation.isDepartmentOfPublication | 0966cedc-9b4d-44f6-932d-51786e48444d | |
| relation.isDepartmentOfPublication.latestForDiscovery | 0966cedc-9b4d-44f6-932d-51786e48444d |
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