Convergence and superconvergence analysis of finite element methods for the time fractional diffusion equation

2020 ◽  
Vol 151 ◽  
pp. 141-160 ◽  
Author(s):  
Meng Li ◽  
Dongyang Shi ◽  
Lifang Pei
2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Zhousheng Ruan ◽  
Zewen Wang ◽  
Wen Zhang

We study a backward problem for a time-fractional diffusion equation, which is formulated into a regularized optimization problem. After solving a sequence of well-posed direct problems by the finite element method, a directly numerical algorithm is proposed for solving the regularized optimization problem. In order to obtain a reasonable regularization solution, we utilize the discrepancy principle with decreasing geometric sequence to choose regularization parameters. One- and two-dimensional examples are given to verify the efficiency and stability of the proposed method.


2018 ◽  
Vol 10 (4) ◽  
pp. 136
Author(s):  
Liwei Shi

Time-fractional partial differential equation is widely applied in a variety of disciplines, its numerical solution has attracted much attention from researchers in recent years. Time-fractional differential equations with interfaces is a more challenging problem because the governing equation has discontinuous coefficients at interfaces and sometimes singular source term exists. In this paper, we propose a Petrov-Galerkin finite element method for solving the two-dimensional time-fractional diffusion equation with interfaces. In this method, a finite difference scheme is employed in time and a Petrov-Galerkin finite element method is employed in space. Extensive numerical experiments show that for a fractional diffusion equation of order $\alpha$ with interfaces, our method gets to $(2-\alpha)$-order accurate in the $L^2$ and $L^{\infty}$ norm.


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