Analysis of a novel finite element method for a modified Cahn-Hilliard-Hele-Shaw system

In this paper, a novel finite element method for solving a modified Cahn-Hilliard-Hele-Shaw system is proposed. The time discretization is based on the convex splitting of the energy functional in the modified Cahn-Hilliard equation, i.e., the high-order nonlinear term and the linear term in the chemical potential are treated explicitly and implicitly, respectively. Designing in this way leads to solving a linear system at each time step, which is much efficient compared to solving a nonlinear system resulting from most existing schemes. The proposed scheme is proved to be unconditionally energy stable and optimally convergent for the phase variable. Numerical results are presented to support our theoretical analysis. (C) 2020 Elsevier B.V. All rights reserved.