An $α$-robust and second-order accurate scheme for a subdiffusion equation

Fuente: arXiv
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Main Authors: Mustapha, Kassem, McLean, William, Dick, Josef
Format: Preprint
Published: 2024
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author Mustapha, Kassem
McLean, William
Dick, Josef
author_facet Mustapha, Kassem
McLean, William
Dick, Josef
contents We investigate a second-order accurate time-stepping scheme for solving a time-fractional diffusion equation with a Caputo derivative of order~$α\in (0,1)$. The basic idea of our scheme is based on local integration followed by linear interpolation. It reduces to the standard Crank--Nicolson scheme in the classical diffusion case, that is, as $α\to 1$. Using a novel approach, we show that the proposed scheme is $α$-robust and second-order accurate in the $L^2(L^2)$-norm, assuming a suitable time-graded mesh. For completeness, we use the Galerkin finite element method for the spatial discretization and discuss the error analysis under reasonable regularity assumptions on the given data. Some numerical results are presented at the end.
format Preprint
id arxiv_https___arxiv_org_abs_2401_04946
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An $α$-robust and second-order accurate scheme for a subdiffusion equation
Mustapha, Kassem
McLean, William
Dick, Josef
Numerical Analysis
We investigate a second-order accurate time-stepping scheme for solving a time-fractional diffusion equation with a Caputo derivative of order~$α\in (0,1)$. The basic idea of our scheme is based on local integration followed by linear interpolation. It reduces to the standard Crank--Nicolson scheme in the classical diffusion case, that is, as $α\to 1$. Using a novel approach, we show that the proposed scheme is $α$-robust and second-order accurate in the $L^2(L^2)$-norm, assuming a suitable time-graded mesh. For completeness, we use the Galerkin finite element method for the spatial discretization and discuss the error analysis under reasonable regularity assumptions on the given data. Some numerical results are presented at the end.
title An $α$-robust and second-order accurate scheme for a subdiffusion equation
topic Numerical Analysis
url https://arxiv.org/abs/2401.04946