Immersed Virtual Element Methods for Elliptic Interface Problems

This article presents an immersed virtual element method for solving a class of interface problems that combines the advantages of both body-fitted mesh methods and unfitted mesh methods. A background body-fitted mesh is generated initially. On those interface elements, virtual element spaces are constructed as solution spaces to local interface problems, and exact sequences can be established for these new spaces involving discontinuous coefficients. The discontinuous coefficients of interface problems are recast as Hodge star operators that is the key to project immersed virtual functions to classic immersed finite element (IFE) functions for computing numerical solutions. The proposed method is capable of handling more complicated interface element configuration, and provides better performance than the conventional penalty-type IFE method for the H(curl)-interface problem. It also brings a connection between various methods such as body-fitted methods, IFE methods, and virtual element methods etc.