Boundary Integral Methods for Particle Diffusion in Complex Geometries: Shielding, Confinement, and Escape

Fuente: arXiv
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Main Authors: Cherry, Jesse, Lindsay, Alan E., Quaife, Bryan D.
Format: Preprint
Published: 2024
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author Cherry, Jesse
Lindsay, Alan E.
Quaife, Bryan D.
author_facet Cherry, Jesse
Lindsay, Alan E.
Quaife, Bryan D.
contents We present a numerical method for the solution of diffusion problems in unbounded planar regions with complex geometries of absorbing and reflecting bodies. Our numerical method applies the Laplace transform to the parabolic problem, yielding a modified Helmholtz equation which is solved with a boundary integral method. Returning to the time domain is achieved by quadrature of the inverse Laplace transform by deforming along the so-called Talbot contour. We demonstrate the method for various complex geometries formed by disjoint bodies of arbitrary shape on which either uniform Dirichlet or Neumann boundary conditions are applied. The use of the Laplace transform bypasses constraints with traditional time-stepping methods and allows for integration over the long equilibration timescales present in diffusion problems in unbounded domains. Using this method, we demonstrate shielding effects where the complex geometry modulates the dynamics of capture to absorbing sets. In particular, we show examples where geometry can guide diffusion processes to particular absorbing sites, obscure absorbing sites from diffusing particles, and even find the exits of confining geometries, such as mazes.
format Preprint
id arxiv_https___arxiv_org_abs_2408_08468
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Boundary Integral Methods for Particle Diffusion in Complex Geometries: Shielding, Confinement, and Escape
Cherry, Jesse
Lindsay, Alan E.
Quaife, Bryan D.
Numerical Analysis
We present a numerical method for the solution of diffusion problems in unbounded planar regions with complex geometries of absorbing and reflecting bodies. Our numerical method applies the Laplace transform to the parabolic problem, yielding a modified Helmholtz equation which is solved with a boundary integral method. Returning to the time domain is achieved by quadrature of the inverse Laplace transform by deforming along the so-called Talbot contour. We demonstrate the method for various complex geometries formed by disjoint bodies of arbitrary shape on which either uniform Dirichlet or Neumann boundary conditions are applied. The use of the Laplace transform bypasses constraints with traditional time-stepping methods and allows for integration over the long equilibration timescales present in diffusion problems in unbounded domains. Using this method, we demonstrate shielding effects where the complex geometry modulates the dynamics of capture to absorbing sets. In particular, we show examples where geometry can guide diffusion processes to particular absorbing sites, obscure absorbing sites from diffusing particles, and even find the exits of confining geometries, such as mazes.
title Boundary Integral Methods for Particle Diffusion in Complex Geometries: Shielding, Confinement, and Escape
topic Numerical Analysis
url https://arxiv.org/abs/2408.08468