High Resolution Interface Representation in Numerical Simulation of Interface Problems Using Finite Element Methods

In fluid-structure interaction problems, the computational domain is divided into a fluid and a structure part. The points in which both subdomains intersect, is called the interface. Forces are coupled through the interface. Therefore, an exact representation of the interface is of great importance. In this talk, we present an approach which assures the representation of the interface with high accuracy. Finite element methods for solving fluid-structure interaction problems exist, where the mesh is aligned with the interface. However, the use of these methods is limited to small deformations of the structure. Large deformations or rotations of the structure, which, for example, are required for the simulation of turbines, are impossible to achieve with these methods. Remeshing is an option to overcome this problem, which is costly and introduces projection errors between the old and the new mesh. We employ a method where the mesh is fixed and the interface between fluids, or fluid and solid, is free to cut through mesh cells. Our approach performs a local modification of the finite element method. Degrees of freedom are reinterpreted implicitly.