The Helmholtz Dirichlet and Neumann problems on piecewise smooth open curves

Fuente: arXiv
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Autores principales: Helsing, Johan, Jiang, Shidong
Formato: Preprint
Publicado: 2024
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author Helsing, Johan
Jiang, Shidong
author_facet Helsing, Johan
Jiang, Shidong
contents A numerical scheme is presented for solving the Helmholtz equation with Dirichlet or Neumann boundary conditions on piecewise smooth open curves, where the curves may have corners and multiple junctions. Existing integral equation methods for smooth open curves rely on analyzing the exact singularities of the density at endpoints for associated integral operators, explicitly extracting these singularities from the densities in the formulation, and using global quadrature to discretize the boundary integral equation. Extending these methods to handle curves with corners and multiple junctions is challenging because the singularity analysis becomes much more complex, and constructing high-order quadrature for discretizing layer potentials with singular and hypersingular kernels and singular densities is nontrivial. The proposed scheme is built upon the following two observations. First, the single-layer potential operator and the normal derivative of the double-layer potential operator serve as effective preconditioners for each other locally. Second, the recursively compressed inverse preconditioning (RCIP) method can be extended to address "implicit" second-kind integral equations. The scheme is high-order, adaptive, and capable of handling corners and multiple junctions without prior knowledge of the density singularity. It is also compatible with fast algorithms, such as the fast multipole method. The performance of the scheme is illustrated with several numerical examples.
format Preprint
id arxiv_https___arxiv_org_abs_2411_05761
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Helmholtz Dirichlet and Neumann problems on piecewise smooth open curves
Helsing, Johan
Jiang, Shidong
Numerical Analysis
Computational Physics
31A10, 45B05, 45E99, 65N99, 65R20
A numerical scheme is presented for solving the Helmholtz equation with Dirichlet or Neumann boundary conditions on piecewise smooth open curves, where the curves may have corners and multiple junctions. Existing integral equation methods for smooth open curves rely on analyzing the exact singularities of the density at endpoints for associated integral operators, explicitly extracting these singularities from the densities in the formulation, and using global quadrature to discretize the boundary integral equation. Extending these methods to handle curves with corners and multiple junctions is challenging because the singularity analysis becomes much more complex, and constructing high-order quadrature for discretizing layer potentials with singular and hypersingular kernels and singular densities is nontrivial. The proposed scheme is built upon the following two observations. First, the single-layer potential operator and the normal derivative of the double-layer potential operator serve as effective preconditioners for each other locally. Second, the recursively compressed inverse preconditioning (RCIP) method can be extended to address "implicit" second-kind integral equations. The scheme is high-order, adaptive, and capable of handling corners and multiple junctions without prior knowledge of the density singularity. It is also compatible with fast algorithms, such as the fast multipole method. The performance of the scheme is illustrated with several numerical examples.
title The Helmholtz Dirichlet and Neumann problems on piecewise smooth open curves
topic Numerical Analysis
Computational Physics
31A10, 45B05, 45E99, 65N99, 65R20
url https://arxiv.org/abs/2411.05761