Three-dimensional acoustic scattering from a penetrable layered cylindrical obstacle in a horizontally stratified ocean waveguide

Athanassoulis, GA; Prospathopoulos, AM

dc.contributor.author	Athanassoulis, GA	en
dc.contributor.author	Prospathopoulos, AM	en
dc.date.accessioned	2014-03-01T01:15:56Z
dc.date.available	2014-03-01T01:15:56Z
dc.date.issued	2000	en
dc.identifier.issn	0001-4966	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13839
dc.subject	Acoustic Scattering	en
dc.subject	Three Dimensional	en
dc.subject.classification	Acoustics	en
dc.subject.other	NORMAL-MODE SOLUTION	en
dc.subject.other	HELMHOLTZ-EQUATION	en
dc.subject.other	WAVE-GUIDE	en
dc.subject.other	PROPAGATION	en
dc.subject.other	EFFICIENT	en
dc.subject.other	OBJECTS	en
dc.title	Three-dimensional acoustic scattering from a penetrable layered cylindrical obstacle in a horizontally stratified ocean waveguide	en
heal.type	journalArticle	en
heal.identifier.primary	10.1121/1.428627	en
heal.identifier.secondary	http://dx.doi.org/10.1121/1.428627	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	In this work, a normal-mode solution is presented for the three-dimensional problem of acoustic scattering from a penetrable horizontally layered cylindrical obstacle in a shallow-water waveguide. The ocean environment around the obstacle is considered horizontally stratified and the bottom is assumed to be rigid. Ln the general case of depth-dependent sound-speed and density profiles (ssdp) the total acoustic field is calculated numerically, while an analytic solution is obtained in the special case of depth-independent ssdp. Numerical results concerning the transmission loss outside and inside single or double-layered cylindrical structures made of acoustic materials are given for a typical depth-dependent ocean environment. Comparisons with the cases of ideally soft and ideally hard cylindrical obstacles [J. Acoust. Sec. Am. 100, 206-218 (1996)] are also made, illustrating the effect of acoustic properties of the obstacle. An important feature, which clearly emerges from the theoretical analysis and the numerical results, is the necessity of including evanescent modes in the calculations, in order to obtain physically meaningful and numerically accurate results. Furthermore, analytical expressions for the scattering cross section of a (penetrable or impenetrable) cylindrical obstacle are derived in terms of the expansion coefficients of the pressure field, and their behavior as frequency increases is numerically investigated. The solution presented in this paper, although addressing a special geometry, provides a means for handling strong discontinuities in both vertical and horizontal directions, and can serve as a benchmark solution to a problem for which no general numerical model exists, i.e., modeling acoustic scattering from a 3D obstacle in a 3D shallow-water waveguide. (C) 2000 Acoustical Society of America. [S0001-4966(00)01204-2].	en
heal.publisher	AMER INST PHYSICS	en
heal.journalName	JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA	en
dc.identifier.doi	10.1121/1.428627	en
dc.identifier.isi	ISI:000086967900011	en
dc.identifier.volume	107	en
dc.identifier.issue	5	en
dc.identifier.spage	2406	en
dc.identifier.epage	2417	en