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A study of rough surface scattering ...

Hastings, Frank Desmond.

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A study of rough surface scattering in electromagnetics, acoustics, and elastodynamics applications using finite-difference time-domain simulations.

Record Type:	Electronic resources : Monograph/item
Title/Author:	A study of rough surface scattering in electromagnetics, acoustics, and elastodynamics applications using finite-difference time-domain simulations./
Author:	Hastings, Frank Desmond.
Description:	125 p.
Notes:	Source: Dissertation Abstracts International, Volume: 59-06, Section: B, page: 2798.
Contained By:	Dissertation Abstracts International59-06B.
Subject:	Physics, Acoustics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9835842
ISBN:	059189369X

A study of rough surface scattering in electromagnetics, acoustics, and elastodynamics applications using finite-difference time-domain simulations.
Hastings, Frank Desmond.

A study of rough surface scattering in electromagnetics, acoustics, and elastodynamics applications using finite-difference time-domain simulations. - 125 p.

Source: Dissertation Abstracts International, Volume: 59-06, Section: B, page: 2798.

Thesis (Ph.D.)--Washington State University, 1997.

The shallow water waveguide contains a number of scattering mechanisms. The air-sea surface and the sediment bottom are two important contributors to the general reverberation level. In this dissertation, we examine surface scattering using the finite-difference time-domain method via Monte Carlo simulations. The FDTD method is a full wave technique that has been widely used to model wave scattering in electromagnetics, acoustics, and elastodynamics. The first problem considered is the air-sea interface. Scattering strengths are computed for rough Dirichlet surfaces which satisfy Gaussian and Pierson-Moskowitz (PM) spectra. The Dirichlet boundary condition can be used to model either a PEC surface for electromagnetics or a pressure release surface for acoustics. A tapered plane wave illuminates the surface for incident angles of 0

ISBN: 059189369XSubjects--Topical Terms:

1019086
Physics, Acoustics.

A study of rough surface scattering in electromagnetics, acoustics, and elastodynamics applications using finite-difference time-domain simulations.
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020 $a 059189369X
035 $a (UnM)AAI9835842
035 $a AAI9835842
040 $a UnM $c UnM
100 1 $a Hastings, Frank Desmond. $3 1929736
245 1 2 $a A study of rough surface scattering in electromagnetics, acoustics, and elastodynamics applications using finite-difference time-domain simulations.
300 $a 125 p.
500 $a Source: Dissertation Abstracts International, Volume: 59-06, Section: B, page: 2798.
500 $a Chair: John B. Schneider.
502 $a Thesis (Ph.D.)--Washington State University, 1997.
520 $a The shallow water waveguide contains a number of scattering mechanisms. The air-sea surface and the sediment bottom are two important contributors to the general reverberation level. In this dissertation, we examine surface scattering using the finite-difference time-domain method via Monte Carlo simulations. The FDTD method is a full wave technique that has been widely used to model wave scattering in electromagnetics, acoustics, and elastodynamics. The first problem considered is the air-sea interface. Scattering strengths are computed for rough Dirichlet surfaces which satisfy Gaussian and Pierson-Moskowitz (PM) spectra. The Dirichlet boundary condition can be used to model either a PEC surface for electromagnetics or a pressure release surface for acoustics. A tapered plane wave illuminates the surface for incident angles of 0 $\ sp\circ $, 45 $\ sp\circ $, 70 $\ sp\circ $, and 80 $\ sp\circ $ (measured from vertical). A second case is considered for the air-sea interface. The forward scattered quasi-near-field pressure is found for a single realization of a PM pressure-release surface. Small errors are more apparent for a single surface realization, and the fields near the surface have a more complex structure. Hence, this is a more numerically challenging problem. The third problem considered is the ocean bottom, which for the frequencies and material parameters considered is well approximated by a lossless fluid interface. Scattering strengths are determined for surfaces with Gaussian and modified power law spectra. A tapered plane wave is used to insonify the surface at incident angles, $\ theta\sb{i} $ = 70 $\ sp\circ $ and $\ theta\sb{i} $ = 80 $\ sp\circ. $ Integral equation results are used for comparison in all of the surface scattering cases, and generally agreement is excellent. The final problem considered is one component of the elastic FDTD implementation which is useful in modeling sediment bottoms for lower frequencies where shear wave effects cannot be ignored. The perfectly matched layer absorbing boundary condition (ABC) taken from the electromagnetics literature is adapted for elastic waves. Broadband and CW simulation tests show that the new ABC has excellent performance.
590 $a School code: 0251.
650 4 $a Physics, Acoustics. $3 1019086
650 4 $a Engineering, Electronics and Electrical. $3 626636
650 4 $a Engineering, Marine and Ocean. $3 1019064
650 4 $a Physical Oceanography. $3 1019163
690 $a 0986
690 $a 0544
690 $a 0547
690 $a 0415
710 2 0 $a Washington State University. $3 678588
773 0 $t Dissertation Abstracts International $g 59-06B.
790 1 0 $a Schneider, John B., $e advisor
790 $a 0251
791 $a Ph.D.
792 $a 1997
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9835842