Numerical solution of the boundary value problem of elliptic equation by Levi function scheme

TL;DR

This paper introduces efficient numerical schemes based on Levi functions for solving elliptic boundary value problems with variable coefficients, reducing computational costs and improving accuracy in inhomogeneous media.

Contribution

It proposes two novel schemes, an adaptive discretization and a meshless dual reciprocity method, for solving volume integrals in Levi function-based solutions.

Findings

Schemes are numerically validated with satisfactory computational efficiency.

Methods achieve uniform accuracy across the domain.

Numerical examples demonstrate the schemes' effectiveness in 2D and 3D cases.

Abstract

For boundary value problem of an elliptic equation with variable coefficients describing the physical field distribution in inhomogeneous media, the Levi function can represent the solution in terms of volume and surface potentials, with the drawback that the volume potential involving in the solution expression requires heavy computational costs as well as the solvability of the integral equations with respect to the density pair. We introduce an modified integral expression for the solution to an elliptic equation in divergence form under the Levi function framework. The well-posedness of the linear integral system with respect to the density functions to be determined is rigorously proved. Based on the singularity decomposition for the Levi function, we propose two schemes to deal with the volume integrals so that the density functions can be solved efficiently. One method is an adaptive discretization scheme (ADS) for computing the integrals with continuous integrands, leading to the uniform accuracy of the integrals in the whole domain, and consequently the efficient computations for the density functions. The other method is the dual reciprocity method (DRM) which is a meshless approach converting the volume integrals into boundary integrals equivalently by expressing the volume density as the combination of the radial basis functions determined by the interior grids. The proposed schemes are justified numerically to be of satisfactory computation costs. Numerical examples in 2-dimensional and 3-dimensional cases are presented to show the validity of the proposed schemes.