Papers by Keyword: Fractional Diffusion Equation

Abstract: Fractional diffusion equations have recently been applied in various area of engineering. In this paper, a new numerical algorithm for solving the fractional diffusion equations with a variable coefficient is proposed. Based on the collocation technique where the shifted Chebyshev polynomials in time and the sinc functions in space are utilized respectively, the problem is reduced to the solution of a system of linear algebraic equations. The procedure is tested and the efficiency of the proposed algorithm is confirmed through the numerical example.

Abstract: Firstly, using matrix transform method, we transform the Riesz space fractional diffusion equation into an ordinary differential equation, and get its analytic solution. Secondly, we use (2,1) Pade approxiation to the exponentinal matrix of the analytic solution and obtain a new difference scheme for solving Riesz space fractional diffusion equation. Finally, we prove that the difference scheme is unconditionally stable.

Abstract: Fisher’s model for grain boundary diffusion considers the lattice and the grain boundary on the same basis by presuming the validity of Fick’s second law for both cases, despite the significant structural differences between them. Recent studies [1-3] have, however, shown that grain boundary diffusion is profoundly different from lattice diffusion. We propose an alternative mathematical formulation that incorporates these structural differences and consequently models grain boundary diffusion phenomena more accurately than Fisher’s model. This is achieved by considering possible deviations from the classical random walk for solute atoms diffusing through grain boundaries. This formalism can also be applied to surface diffusion and triple junction diffusion.