A fast-convergent spectral-fem for harmonic wave propagation in inhomogeneous layered waveguides

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dc.contributor.author Belibassakis, KA en
dc.contributor.author Papathanasiou, TK en
dc.contributor.author Filopoulos, SP en
dc.date.accessioned 2014-03-01T02:53:32Z
dc.date.available 2014-03-01T02:53:32Z
dc.date.issued 2012 en
dc.identifier.issn 10986189 en
dc.identifier.uri http://hdl.handle.net/123456789/36393
dc.relation.uri http://www.scopus.com/inward/record.url?eid=2-s2.0-84866107421&partnerID=40&md5=34e382993b3cb5d6bbc9b6eb68d7abd6 en
dc.subject Finite elements en
dc.subject Local-mode series en
dc.subject Non-uniform waveguides en
dc.subject Spectral methods en
dc.subject Stratified waveguides en
dc.title A fast-convergent spectral-fem for harmonic wave propagation in inhomogeneous layered waveguides en
heal.type conferenceItem en
heal.publicationDate 2012 en
heal.abstract A fast-convergent spectral model is presented for harmonic wave propagation and scattering problems in stratified, non uniform waveguides, governed by the Helmholtz equation. The method is based on a local mode series expansion, obtained by utilizing variable crosssection eigenfunction systems, which are defined through the solution of eigenvalue problems formulated along the waveguide, and including additional modes accounting for the effects of inhomogeneous boundaries and/or interfaces. The additional modes provide an implicit summation of the slowly convergent part of the local-mode series, rendering the remaining part to be fast convergent, increasing the efficiency of the method, especially in long-range propagation applications. Using the enhanced representation, in conjunction with an energy-type variational principle, a coupled-mode system of equations is derived for the determination of the unknown modal-amplitude functions. In order to treat the local vertical eigenvalue problems in the case of multilayered waveguides h- and p- Finite Element Methods have been applied exhibiting robustness and good rates of convergence. On the basis of the above, the coefficients of the coupled-mode system are calculated by numerical integration. Finally, the solution of the present coupled-mode system is obtained by using a finite difference scheme based on a uniform grid and using second-order central differences to approximate derivatives. Numerical examples are presented in simple 2D acoustic propagation problems, illustrating the role and significance of the additional mode(s) and the efficiency of the present model, that can be naturally extended to treat propagation and scattering problems in more complicated 3D waveguides. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE). en
heal.journalName Proceedings of the International Offshore and Polar Engineering Conference en
dc.identifier.spage 479 en
dc.identifier.epage 486 en

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