A conservative numerical method for the Cahn–Hilliard equation in complex domains

We propose an efficient finite difference scheme for solving the Cahn–Hilliard equation with a variable mobility in complex domains. Our method employs a type of unconditionally gradient stable splitting discretization. We also extend the scheme to compute the Cahn–Hilliard equation in arbitrarily shaped domains. We prove the mass conservation property of the proposed discrete scheme for complex domains. The resulting discretized equations are solved using a multigrid method. Numerical simulations are presented to demonstrate that the proposed scheme can deal with complex geometries robustly. Furthermore, the multigrid efficiency is retained even if the embedded domain is present.

► We propose a numerical method for the Cahn–Hilliard equation in complex domains.
► We prove the mass conservation property of the proposed scheme for complex domains.
► We propose an efficient multigrid method in nonrectangular domains.