Improvements for the ultra weak variational formulation
SUMMARYIn this paper, we investigate strategies to improve the accuracy and efficiency of the ultra weak variational formulation (UWVF) of the Helmholtz equation. The UWVF is a Trefftz type, nonpolynomial method using basis functions derived from solutions of the adjoint Helmholtz equation. We shall...
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Published in | International journal for numerical methods in engineering Vol. 94; no. 6; pp. 598 - 624 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Chichester
Blackwell Publishing Ltd
11.05.2013
Wiley Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | SUMMARYIn this paper, we investigate strategies to improve the accuracy and efficiency of the ultra weak variational formulation (UWVF) of the Helmholtz equation. The UWVF is a Trefftz type, nonpolynomial method using basis functions derived from solutions of the adjoint Helmholtz equation. We shall consider three choices of basis function: propagating plane waves (original choice), Bessel basis functions, and evanescent wave basis functions. Traditionally, two‐dimensional triangular elements are used to discretize the computational domain. However, the element shapes affect the conditioning of the UWVF. Hence, we investigate the use of different element shapes aiming to lower the condition number and number of degrees of freedom. Our results include the first tests of a plane wave method on meshes of mixed element types. In many modeling problems, evanescent waves occur naturally and are challenging to model. Therefore, we introduce evanescent wave basis functions for the first time in the UWVF to tackle rapidly decaying wave modes. The advantages of an evanescent wave basis are verified by numerical simulations on domains including curved interfaces.Copyright © 2013 John Wiley & Sons, Ltd. |
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Bibliography: | National Science Foundation - No. DMS-1216620 ArticleID:NME4469 istex:4ABA71600CAFD4D34BD3579975FA0576CAC59355 ark:/67375/WNG-76437P8M-8 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0029-5981 1097-0207 |
DOI: | 10.1002/nme.4469 |