Novel, linear, decoupled and unconditionally energy stable numerical methods for the coupled Cahn–Hilliard equations

Abstract

Abstract This paper uses a novel numerical approach to approximate the coupled Cahn–Hilliard equations, which are a highly nonlinear system depicting the phase separation of the homopolymer and copolymer mixtures. The new method is named 3S-IEQ, and its construction and calculation are more straightforward than the invariant energy quadratization and scalar auxiliary variable methods. Notably, we only need to solve two linear decoupled constant-coefficient equations at each time step. Numerical simulations are shown

Keywords

• Coupled Cahn–Hilliard equations
• Unconditionally energy stable
• Lagrange multiplier approach