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Resonance problems in acoustic waveguides

Nannen, Lothar and Koch, Werner and Hein, Stefan (2010) Resonance problems in acoustic waveguides. 1st EAA - EuroRegio Congress on Sound and Vibration, 15.-18. Sept. 2010, Ljubljana, Slovenia. ISBN 978-961-269-283-4.

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Abstract

Acoustic resonance problems in closed systems can be solved numerically with finite element methods. The resulting real resonances become complex, if the system changes to an open system with an unbounded domain. While for a completely open system only damped resonances exist, laterally confined domains can sustain localized, truly trapped modes with nominally zero radiation loss. These discrete resonant modes cannot be excited linearly by continuous propagating duct modes due to symmetry constraints. If the symmetry of the geometry is broken the trapped modes become highly localized quasi-trapped modes which can interfere with the propagating duct modes. Since standard finite element methods are restricted to bounded domains, in a numerical treatment of such problems so called transparent or non-reflecting boundary conditions are needed. In this paper two different types of transparent boundary conditions namely the complex scaling method and the Hardy space infinite element method, are used to compute resonances as well as transmission and reflection coefficients for symmetric obstacles in a two dimensional waveguide.

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Resonance problems in acoustic waveguides
Authors:
AuthorsInstitution or Email of Authors
Nannen, LotharUniversität Göttingen
Koch, WernerUNSPECIFIED
Hein, StefanUNSPECIFIED
Date:September 2010
Refereed publication:No
In SCOPUS:No
In ISI Web of Science:No
Series Name:Book of Abstracts, Conference Proceedings on CD-ROM
ISBN:978-961-269-283-4
Status:Published
Keywords:Fano resonance, acoustic waveguide, complex scaling, perfectly matched layer, Hardy space infinite element method
Event Title:1st EAA - EuroRegio Congress on Sound and Vibration
Event Location:Ljubljana, Slovenia
Event Type:international Conference
Event Dates:15.-18. Sept. 2010
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Helicopters
Deposited By: Dr.-Ing. Stefan Hein
Deposited On:14 Oct 2010 14:07
Last Modified:14 Oct 2010 14:07

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