Asymptotically compatible energy and dissipation law of the nonuniform L2-$1_σ$ scheme for time fractional Allen-Cahn model

Fuente: arXiv
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Autori principali: Liao, Hong-lin, Zhu, Xiaohan, Sun, Hong
Natura: Preprint
Pubblicazione: 2023
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author Liao, Hong-lin
Zhu, Xiaohan
Sun, Hong
author_facet Liao, Hong-lin
Zhu, Xiaohan
Sun, Hong
contents We build an asymptotically compatible energy of the variable-step L2-$1_σ$ scheme for the time-fractional Allen-Cahn model with the Caputo's fractional derivative of order $α\in(0,1)$, under a weak step-ratio constraint $τ_k/τ_{k-1}\geq r_{\star}(α)$ for $k\ge2$, where $τ_k$ is the $k$-th time-step size and $r_{\star}(α)\in(0.3865,0.4037)$ for $α\in(0,1)$. It provides a positive answer to the open problem in [J. Comput. Phys., 414:109473], and, to the best of our knowledge, it is the first second-order nonuniform time-stepping scheme to preserve both the maximum bound principle and the energy dissipation law of time-fractional Allen-Cahn model. The compatible discrete energy is constructed via a novel discrete gradient structure of the second-order L2-$1_σ$ formula by a local-nonlocal splitting technique. It splits the discrete fractional derivative into two parts: one is a local term analogue to the trapezoid rule of the first derivative and the other is a nonlocal summation analogue to the L1 formula of Caputo derivative. Numerical examples with an adaptive time-stepping strategy are provided to show the effectiveness of our scheme and the asymptotic properties of the associated modified energy.
format Preprint
id arxiv_https___arxiv_org_abs_2311_13216
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Asymptotically compatible energy and dissipation law of the nonuniform L2-$1_σ$ scheme for time fractional Allen-Cahn model
Liao, Hong-lin
Zhu, Xiaohan
Sun, Hong
Numerical Analysis
65M12, 65M06, 35Q99, 74A50
We build an asymptotically compatible energy of the variable-step L2-$1_σ$ scheme for the time-fractional Allen-Cahn model with the Caputo's fractional derivative of order $α\in(0,1)$, under a weak step-ratio constraint $τ_k/τ_{k-1}\geq r_{\star}(α)$ for $k\ge2$, where $τ_k$ is the $k$-th time-step size and $r_{\star}(α)\in(0.3865,0.4037)$ for $α\in(0,1)$. It provides a positive answer to the open problem in [J. Comput. Phys., 414:109473], and, to the best of our knowledge, it is the first second-order nonuniform time-stepping scheme to preserve both the maximum bound principle and the energy dissipation law of time-fractional Allen-Cahn model. The compatible discrete energy is constructed via a novel discrete gradient structure of the second-order L2-$1_σ$ formula by a local-nonlocal splitting technique. It splits the discrete fractional derivative into two parts: one is a local term analogue to the trapezoid rule of the first derivative and the other is a nonlocal summation analogue to the L1 formula of Caputo derivative. Numerical examples with an adaptive time-stepping strategy are provided to show the effectiveness of our scheme and the asymptotic properties of the associated modified energy.
title Asymptotically compatible energy and dissipation law of the nonuniform L2-$1_σ$ scheme for time fractional Allen-Cahn model
topic Numerical Analysis
65M12, 65M06, 35Q99, 74A50
url https://arxiv.org/abs/2311.13216