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Main Authors: Wang, Siyuan, Xia, Qing
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.14346
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author Wang, Siyuan
Xia, Qing
author_facet Wang, Siyuan
Xia, Qing
contents This paper develops a finite-difference analogue of the boundary integral/element method for the numerical solution of two-dimensional exterior scattering from scatterers of arbitrary shapes. The discrete fundamental solution, known as the lattice Green's function (LGF), for the Helmholtz equation on an infinite lattice is derived and employed to construct boundary algebraic equations through the discrete potentials framework. Unlike the continuous fundamental solution used in boundary integral methods, the LGF introduces no singularity, which simplifies numerical implementation. Boundary conditions are incorporated through local Lagrange interpolation on unfitted cut cells. The resulting method retains key advantages of boundary integral approaches-including dimension reduction and the absence of artificial boundary conditions--while enabling finite differences for complex geometries. Numerical results demonstrate the accuracy and robustness of the method for various scatterers, including circular, triangular, and multiple-body configurations.
format Preprint
id arxiv_https___arxiv_org_abs_2511_14346
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unfitted Lattice Green's Function Method for Exterior Scattering in Complex Geometry
Wang, Siyuan
Xia, Qing
Numerical Analysis
This paper develops a finite-difference analogue of the boundary integral/element method for the numerical solution of two-dimensional exterior scattering from scatterers of arbitrary shapes. The discrete fundamental solution, known as the lattice Green's function (LGF), for the Helmholtz equation on an infinite lattice is derived and employed to construct boundary algebraic equations through the discrete potentials framework. Unlike the continuous fundamental solution used in boundary integral methods, the LGF introduces no singularity, which simplifies numerical implementation. Boundary conditions are incorporated through local Lagrange interpolation on unfitted cut cells. The resulting method retains key advantages of boundary integral approaches-including dimension reduction and the absence of artificial boundary conditions--while enabling finite differences for complex geometries. Numerical results demonstrate the accuracy and robustness of the method for various scatterers, including circular, triangular, and multiple-body configurations.
title Unfitted Lattice Green's Function Method for Exterior Scattering in Complex Geometry
topic Numerical Analysis
url https://arxiv.org/abs/2511.14346