Acoustic field induced in spheres with inhomogeneous density by external sources

Kokkorakis, GC; Fikioris, JG

dc.contributor.author	Kokkorakis, GC	en
dc.contributor.author	Fikioris, JG	en
dc.date.accessioned	2014-03-01T01:19:52Z
dc.date.available	2014-03-01T01:19:52Z
dc.date.issued	2004	en
dc.identifier.issn	0001-4966	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15734
dc.subject.classification	Acoustics	en
dc.subject.other	Electromagnetic fields	en
dc.subject.other	Functions	en
dc.subject.other	Integral equations	en
dc.subject.other	Orthogonal expansions	en
dc.subject.other	Spherical harmonics	en
dc.subject.other	Acoustic fields	en
dc.subject.other	acoustics	en
dc.subject.other	electromagnetic field	en
dc.subject.other	accuracy	en
dc.subject.other	acoustics	en
dc.subject.other	article	en
dc.subject.other	compression	en
dc.subject.other	density	en
dc.subject.other	electromagnetic field	en
dc.subject.other	mathematical analysis	en
dc.subject.other	priority journal	en
dc.title	Acoustic field induced in spheres with inhomogeneous density by external sources	en
heal.type	journalArticle	en
heal.identifier.primary	10.1121/1.1635410	en
heal.identifier.secondary	http://dx.doi.org/10.1121/1.1635410	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	Acoustic or electromagnetic fields induced in the interior of inhomogeneous penetrable bodies by external sources can be evaluated via well-known volume integral equations. For bodies of arbitrary shape and/or composition, for which separation of variables fails, a direct attack for the solution of these integral equations is the only available approach. In a previous paper by the same authors the scalar (acoustic) field in inhomogeneous spheres of arbitrary compressibility, but with constant density, was considered. In the present one the direct hybrid (analytical-numerical) method applied to the much simpler integral equation for spheres with constant density is generalized to densities that vary with r, theta, or even phi. This extension is by no means trivial, owing to the appearance of the derivatives of both the density and the unknown function in the volume integral, a fact necessitating a more subtle and accuracy-sensitive approach. Again, the spherical shape allows use of the orthogonal spherical harmonics and of Dini's expansions of a general type for the radial functions. The convergence of the latter, shown to be superior to other possible sets of orthogonal expansions, can be further optimized by the proper selection of a crucial parameter in their eigenvalue equation. (C) 2004 Acoustical Society of America.	en
heal.publisher	ACOUSTICAL SOC AMER AMER INST PHYSICS	en
heal.journalName	Journal of the Acoustical Society of America	en
dc.identifier.doi	10.1121/1.1635410	en
dc.identifier.isi	ISI:000188944100004	en
dc.identifier.volume	115	en
dc.identifier.issue	2	en
dc.identifier.spage	478	en
dc.identifier.epage	487	en