Solvability and approximation of two-side conservative fractional diffusion problems with variable-Coefficient based on least-Squares

Autor: Huanzhen Chen, Suxiang Yang, Vincent J. Ervin, Hong Wang
Rok vydání: 2021
Předmět:
Zdroj: Applied Mathematics and Computation. 406:126229
ISSN: 0096-3003
DOI: 10.1016/j.amc.2021.126229
Popis: We investigate solvability theory and numerical simulation for two-side conservative fractional diffusion equations (CFDE) with a variable-coefficient a ( x ) . We introduce σ = − a D p as an intermediate variable to isolate a ( x ) from the nonlocal operator, and then apply the least-squares method to obtain a mixed-type variational formulation. Correspondingly, solution space is split into a regular space and a kernel-dependent space. The solution p and σ are then represented as a sum of a regular part and a kernel-dependent singular part. Doing so, a new regularity theory is established, which extends those regularity results for the one side CFDE in [23, 36], and for the fractional Laplace equation corresponding to θ = 1 / 2 in [37, 38], to general CFDE with variable diffusive coefficients and for 0 θ 1 . Then, we design a kernel-independent least-squares mixed finite element approximation scheme (LSMFE). Theoretical analysis and numerical simulation demonstrate that the LSMFE can capture the singular part of the solution, approximate the solution with optimal-order accuracy, and can be easily implemented.
Databáze: OpenAIRE