首页|Caputo型时间分数阶变系数扩散方程的局部间断Galerkin方法

Caputo型时间分数阶变系数扩散方程的局部间断Galerkin方法

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提出一种带有Caputo导数的时间分数阶变系数扩散方程的数值解法.方程的解在初始时刻附近通常具有弱正则性,采用非一致网格上的L1公式离散时间分数阶导数,并使用局部间断Galerkin(local discontinuous Galerkin,LDG)方法离散空间导数,给出方程的全离散格式.基于离散的分数阶Gronwall不等式,证明了格式的数值稳定性和收敛性,且所得结果关于α是鲁棒的,即当α→1-时不会发生爆破.最后,通过数值算例验证理论分析的结果.
Local discontinuous Galerkin finite element method for the Caputo-type diffusion equation with variable coefficient
We present an efficient method for seeking the numerical solution of a Caputo-type diffusion equation with a variable coefficient.Since the solution of such an equation is likely to have a weak singularity near the initial time,the time-fractional derivative is discretized using the L1 formula on nonuniform meshes.For spatial derivative,we employ the local discontinuous Galerkin method to derive a fully discrete scheme.Based on a dis-crete fractional Gronwall inequality,the numerical stability and convergence of the derived scheme are proven which are both α-robust,that is,the bounds obtained do not blow up as α → 1-.Finally,numerical experiments are displayed to confirm the theoretical results.

local discontinuous Galerkin methodnonuniform time meshα-robustweak singularityvariable coefficient

代巧巧、李东霞

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上海大学理学院,上海 200444

局部间断Galerkin方法 非一致时间网格 α-鲁棒 弱正则性 变系数

国家自然科学基金资助项目

11671251

2024

上海大学学报(自然科学版)
上海大学

上海大学学报(自然科学版)

CSTPCD北大核心
影响因子:0.579
ISSN:1007-2861
年,卷(期):2024.30(1)
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