23-08-2019 | Original Paper | Issue 3/2020

Numerical approximation of the fractional Cahn-Hilliard equation by operator splitting method
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- Numerical Algorithms > Issue 3/2020
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Abstract
In this paper, we consider a fast explicit operator splitting method for a fractional Cahn-Hilliard equation with spatial derivative \((-{\varDelta })^{\frac {\alpha }{2}}\)(α ∈ (1,2]), where the choice α = 2 corresponds to the classical Cahn-Hilliard equation. The original problem is split into linear and nonlinear subproblems. For the linear part, the pseudo-spectral method is adopted, and thus an ordinary differential equation is obtained. For the nonlinear part, a second-order SSP-RK method together with the pseudo-spectral method is used. The stability and convergence of the proposed method in L2-norm are studied. We also carry out a comparative study of two classical definitions for fractional Laplacian \((-{\varDelta })^{\frac {\alpha }{2}}\), and numerical results obtained using computational simulation of the fractional Cahn-Hilliard equation for a variety of choices of fractional order α are presented. It is observed that the fractional order α controls the sharpness of the interface, which is typically diffusive in integer-order phase-field models.