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Computational Science, Engineering & Technology Series
ISSN 1759-3158 CSETS: 18
COMPUTATIONAL METHODS FOR ACOUSTICS PROBLEMS Edited by: F. Magoulès
Chapter 4
Stabilized Time-Discontinuous Galerkin Methods with Applications to Acoustics L.L. Thompson1, P. Kunthong2 and S. Subbarayalu3
1Department of Mechanical Engineering, Clemson University, SC, United States of America L.L. Thompson, P. Kunthong, S. Subbarayalu, "Stabilized Time-Discontinuous Galerkin Methods with Applications to Acoustics", in F. Magoulès, (Editor), "Computational Methods for Acoustics Problems", Saxe-Coburg Publications, Stirlingshire, UK, Chapter 4, pp 99-126, 2008. doi:10.4203/csets.18.4
Keywords: time-discontinuous Galerkin, acoustics, waves, hyperbolic systems, spacetime,
multi-pass iterative.
Abstract
The time-discontinuous Galerkin (TDG) method provides high-order accuracy with
desirable C and L stability for second-order hyperbolic systems governing acoustics.
C and L stability provide asymptotic annihilation of high frequency response due to
any spurious resolution of small scales. In order to retain the high-order accuracy and
stability properties of the parent TDG method while gaining efficiency comparable
with standard second-order accurate single-step/single-solve (SS/SS) time stepping
algorithms, generalised gradients of residuals of the governing equations are added
to the standard TDG variational equation. Using this stabilized framework, together
with optimal design of temporal approximations and time-scales, efficient multi-pass
iterative solution algorithms are developed which maintain C and L stability, provide
high-order accuracy in only two or three iterative passes, and can easily be implemented
in standard finite element codes. An alternative decoupling strategy which
uses a spectral decomposition of the time arrays is also developed and used to efficiently
solve the space-time matrix equations resulting from the TDG method. This
approach is especially amendable for parallel implementation. Local adaptive space-time
finite element strategies based on the TDG method are also presented.
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