LDG method for solving spatial and temporal fractional nonlinear convection-diffusion equations

TL;DR

This paper introduces a local discontinuous Galerkin method with Legendre basis functions for solving nonlinear fractional convection-diffusion equations, achieving stability and optimal convergence rates.

Contribution

It develops a novel DG method tailored for space and time-fractional equations, with proven stability and high-order convergence.

Findings

Method is stable and converges optimally.

Numerical results confirm efficiency and accuracy.

Appropriate basis functions enhance solution quality.

Abstract

This paper focuses on a nonlinear convection-diffusion equation with space and time-fractional Laplacian operators of orders $1<\beta<2$ and $0<\alpha\leq1$, respectively. We develop local discontinuous Galerkin methods, including Legendre basis functions, for a solution to this class of fractional diffusion problem, and prove stability and optimal order of convergence $O(h^{k+1}+(\Delta t)^{1+\frac{p}{2}}+p^2)$. This technique turns the equation into a system of first-order equations and approximates the solution by selecting the appropriate basis functions. Regarding accuracy and stability, the basis functions greatly improve the method. According to the numerical results, the proposed scheme performs efficiently and accurately in various conditions and meets the optimal order of convergence.