An Efficient Finite Difference-Based PML Technique for Acoustic Scattering Problems

Fuente: arXiv
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Main Authors: Han, Bin, Sim, Jiwoon
Format: Preprint
Published: 2025
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author Han, Bin
Sim, Jiwoon
author_facet Han, Bin
Sim, Jiwoon
contents The acoustic scattering problem is modeled by the exterior Helmholtz equation, which is challenging to solve due to both the unboundedness of the domain and the high dispersion error, known as the pollution effect. We develop high-order compact finite difference methods (FDMs) in polar coordinates to numerically solve the problem with multiple arbitrarily shaped scatterers. The unbounded domain is effectively truncated and compressed via perfectly matched layers (PMLs), while the pollution effect is handled by the high order of our method and a novel pollution minimization technique. This technique is easy to implement, rigorously proven to be effective and shows superior performance in our numerous numerical results. The FDMs we propose in regular polar coordinates achieve fourth consistency order. Yet, combined with exponential stretching and mesh refinement, we can reach sixth consistency order by slightly enlarging the stencil at certain locations. Our numerical examples demonstrate that the proposed FDMs are effective and robust under various wavenumbers, PML layer thickness and shapes of scatterers.
format Preprint
id arxiv_https___arxiv_org_abs_2510_23898
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An Efficient Finite Difference-Based PML Technique for Acoustic Scattering Problems
Han, Bin
Sim, Jiwoon
Numerical Analysis
65N06, 65N50, 76B15, 35J05
The acoustic scattering problem is modeled by the exterior Helmholtz equation, which is challenging to solve due to both the unboundedness of the domain and the high dispersion error, known as the pollution effect. We develop high-order compact finite difference methods (FDMs) in polar coordinates to numerically solve the problem with multiple arbitrarily shaped scatterers. The unbounded domain is effectively truncated and compressed via perfectly matched layers (PMLs), while the pollution effect is handled by the high order of our method and a novel pollution minimization technique. This technique is easy to implement, rigorously proven to be effective and shows superior performance in our numerous numerical results. The FDMs we propose in regular polar coordinates achieve fourth consistency order. Yet, combined with exponential stretching and mesh refinement, we can reach sixth consistency order by slightly enlarging the stencil at certain locations. Our numerical examples demonstrate that the proposed FDMs are effective and robust under various wavenumbers, PML layer thickness and shapes of scatterers.
title An Efficient Finite Difference-Based PML Technique for Acoustic Scattering Problems
topic Numerical Analysis
65N06, 65N50, 76B15, 35J05
url https://arxiv.org/abs/2510.23898