We consider high order finite difference approximations to the Helmholtz equation in an exterior domain. We include a simplified absorbing boundary condition to approximate the Sommerfeld radiation condition. This yields a large, but sparse, complex system, which is not self-adjoint and not positive definite. We discretize the equation with a compact fourth or sixth order accurate scheme. We solve this large system of linear equations with a Krylov subspace iterative method. Since the method converges slowly, a preconditioner is introduced, which is a Helmholtz equation but with a modified complex wavenumber. This is discretized by a second or fourth order compact scheme. The system is solved by BICGSTAB with multigrid used for the preconditioner. We study, both by Fourier analysis and computations this preconditioned system especially for the effects of high order discretizations.
Mots clés : Helmholtz equation, high order compact schemes
@article{M2AN_2012__46_3_647_0, author = {Erlangga, Yogi and Turkel, Eli}, title = {Iterative schemes for high order compact discretizations to the exterior {Helmholtz} equation}, journal = {ESAIM: Mathematical Modelling and Numerical Analysis }, pages = {647--660}, publisher = {EDP-Sciences}, volume = {46}, number = {3}, year = {2012}, doi = {10.1051/m2an/2011063}, mrnumber = {2877369}, zbl = {1272.65082}, language = {en}, url = {http://www.numdam.org/articles/10.1051/m2an/2011063/} }
TY - JOUR AU - Erlangga, Yogi AU - Turkel, Eli TI - Iterative schemes for high order compact discretizations to the exterior Helmholtz equation JO - ESAIM: Mathematical Modelling and Numerical Analysis PY - 2012 SP - 647 EP - 660 VL - 46 IS - 3 PB - EDP-Sciences UR - http://www.numdam.org/articles/10.1051/m2an/2011063/ DO - 10.1051/m2an/2011063 LA - en ID - M2AN_2012__46_3_647_0 ER -
%0 Journal Article %A Erlangga, Yogi %A Turkel, Eli %T Iterative schemes for high order compact discretizations to the exterior Helmholtz equation %J ESAIM: Mathematical Modelling and Numerical Analysis %D 2012 %P 647-660 %V 46 %N 3 %I EDP-Sciences %U http://www.numdam.org/articles/10.1051/m2an/2011063/ %R 10.1051/m2an/2011063 %G en %F M2AN_2012__46_3_647_0
Erlangga, Yogi; Turkel, Eli. Iterative schemes for high order compact discretizations to the exterior Helmholtz equation. ESAIM: Mathematical Modelling and Numerical Analysis , Tome 46 (2012) no. 3, pp. 647-660. doi : 10.1051/m2an/2011063. http://www.numdam.org/articles/10.1051/m2an/2011063/
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