Stability and error estimation based on a difference-spectral approximation for the Cahn–Hilliard equation in complex domains
摘要
In this paper, we introduce and investigate a novel numerical method for solving the Cahn–Hilliard equation in two-dimensional complex domains by employing region transformation. Initially, we convert the fourth-order equation into a second-order coupled system and formulate its first- and second-order semi-implicit schemes. Afterwards, we transform them into the polar coordinates equivalents. By introducing a category of weighted Sobolev spaces, we elaborate on fully discrete schemes and offer a theoretical validation of their stability. In particular, the introduction of pole singularities and the nonlinearity of the coupling problem pose significant challenges to theoretical analysis. To address these challenges, we introduce a novel class of projection operators and establish their approximation properties. Leveraging these properties, we provide error estimates for the approximate solutions. To validate our theoretical insights and algorithm’s efficacy, we conclude with a series of numerical examples.