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This paper is devoted to the numerical analysis of a piecewise constant discontinuous Galerkin method for time fractional subdiffusion problems. The regularity of weak solution is firstly established by using variational approach and…

Numerical Analysis · Mathematics 2022-02-22 Binjie Li , Hao Luo , Xiaoping Xie

A singularly perturbed convection-diffusion problem,posed on the unit square in $\mathbb{R}^2$, is studied; its solution has both exponential and characteristic boundary layers. The problem is solved numerically using the local…

Numerical Analysis · Mathematics 2022-09-22 Yao Cheng , Martin Stynes

We investigate semi-discrete numerical schemes based on the standard Galerkin and lumped mass Galerkin finite element methods for an initial-boundary value problem for homogeneous fractional diffusion problems with non-smooth initial data.…

Numerical Analysis · Mathematics 2013-03-13 Bangti Jin , Raytcho Lazarov , Joseph Pasciak , Zhi Zhou

We investigate the error of the (semidiscrete) Galerkin method applied to a semilinear subdiffusion equation in the presence of a nonsmooth initial data. The diffusion coefficient is allowed to depend on time. It is well-known that in such…

Numerical Analysis · Mathematics 2022-03-01 Łukasz Płociniczak

The tempered fractional diffusion equation could be recognized as the generalization of the classic fractional diffusion equation that the truncation effects are included in the bounded domains. This paper focuses on designing the high…

Numerical Analysis · Mathematics 2020-01-03 Leilei Wei , Yinnian He

This paper focuses on the adaptive discontinuous Galerkin (DG) methods for the tempered fractional (convection) diffusion equations. The DG schemes with interior penalty for the diffusion term and numerical flux for the convection term are…

Numerical Analysis · Mathematics 2020-06-16 Xudong Wang , Weihua Deng

We consider the initial/boundary value problem for the fractional diffusion and diffusion-wave equations involving a Caputo fractional derivative in time. We develop two "simple" fully discrete schemes based on the Galerkin finite element…

Numerical Analysis · Mathematics 2015-10-13 Bangti Jin , Raytcho Lazarov , Zhi Zhou

We consider the initial boundary value problem for the inhomogeneous time-fractional diffusion equation with a homogeneous Dirichlet boundary condition and a nonsmooth right hand side data in a bounded convex polyhedral domain. We analyze…

Numerical Analysis · Mathematics 2013-07-04 Bangti Jin , Raytcho Lazarov , Joseph Pasciak , Zhi Zhou

We present a novel Discontinuous Galerkin Finite Element Method for wave propagation problems. The method employs space-time Trefftz-type basis functions that satisfy the underlying partial differential equations and the respective…

Computational Physics · Physics 2015-05-19 Fritz Kretzschmar , Sascha Schnepp , Igor Tsukerman , Thomas Weiland

This paper analyzes a space-time finite element method for fractional wave problems. The method uses a Petrov-Galerkin type time-stepping scheme to discretize the time fractional derivative of order $ \gamma $ ($1<\gamma<2$). We establish…

Numerical Analysis · Mathematics 2018-03-12 Binjie Li , Hao Luo , Xiaoping Xie

We propose a hybridizable discontinuous Galerkin (HDG) finite element method to approximate the solution of the time dependent drift-diffusion problem. This system involves a nonlinear convection diffusion equation for the electron…

Numerical Analysis · Mathematics 2018-11-27 Gang Chen , Peter Monk , Yangwen Zhang

A direct discontinuous Galerkin (DDG) finite element method is developed for solving fractional convection-diffusion and Schr\"{o}dinger type equations with a fractional Laplacian operator of order $\alpha$ $(1<\alpha<2)$. The fractional…

Numerical Analysis · Mathematics 2017-08-16 Tarek Aboelenen

This paper analyzes a time-stepping discontinuous Galerkin method for modified anomalous subdiffusion problems with two time fractional derivatives of orders $ \alpha $ and $ \beta $ ($ 0 < \alpha < \beta < 1 $). The stability of this…

Numerical Analysis · Mathematics 2017-11-16 Binjie Li , Hao Luo , Xiaoping Xie

In this article a simplified weak Galerkin finite element method is developed for the Dirichlet boundary value problem of convection-diffusion-reaction equations. The simplified weak Galerkin method utilizes only the degrees of freedom on…

Numerical Analysis · Mathematics 2018-08-29 Yujie Liu , Junping Wang

We present a full space-time numerical solution of the advection-diffusion equation using a continuous Galerkin finite element method on conforming meshes. The Galerkin/least-square method is employed to ensure stability of the discrete…

Numerical Analysis · Mathematics 2024-11-25 Biswajit Khara , Kumar Saurabh , Robert Dyja , Anupam Sharma , Baskar Ganapathysubramanian

This article devises a new primal-dual weak Galerkin finite element method for the convection-diffusion equation. Optimal order error estimates are established for the primal-dual weak Galerkin approximations in various discrete norms and…

Numerical Analysis · Mathematics 2020-01-22 Waixiang Cao , Chunmei Wang

A singularly perturbed convection-diffusion problem posed on the unit square in $\mathbb{R}^2$, whose solution has exponential boundary layers, is solved numerically using the local discontinuous Galerkin (LDG) method with piecewise…

Numerical Analysis · Mathematics 2022-06-20 Yao Cheng , Shan Jiang , Martin Stynes

Considering fractional fast diffusion equations on bounded open polyhedral domains in $\mathbb{R}^N$, we give a fully Galerkin approximation of the solutions by $C^0$-piecewise linear finite elements in space and backward Euler…

Numerical Analysis · Mathematics 2019-12-18 Dongxue Li , Youquan Zheng

In this article, we consider discrete schemes for a fractional diffusion equation involving a tempered fractional derivative in time. We present a semi-discrete scheme by using the local discontinuous Galerkin (LDG) discretization in the…

Numerical Analysis · Mathematics 2017-04-27 Xiaorui Sun , Fengfqun Zhao , Can Li

Linear wave equations sourced by a Dirac delta distribution $\delta(x)$ and its derivative(s) can serve as a model for many different phenomena. We describe a discontinuous Galerkin (DG) method to numerically solve such equations with…

Numerical Analysis · Mathematics 2023-07-03 Scott E. Field , Sigal Gottlieb , Gaurav Khanna , Ed McClain