Spline-based space-time finite element approach for fluid-structure interaction problems with a focus on fully enclosed domains

Non-Uniform Rational B-Spline (NURBS) surfaces are commonly used within Computer-Aided Design (CAD) tools to represent geometric objects. When using isogeometric analysis (IGA), it is possible use such NURBS geometries for numerical directly. Analyzing fluid flows, however, requires complex three-dimensional flow domains. Defining a parametrization of volumetric domains can be challenging and still an ongoing topic in the IGA community. With recently developed NURBS-enhanced finite element method (NEFEM), favorable characteristics standard method. This achieved by enhancing elements touching boundary geometry itself. In current work, new variation NEFEM introduced, which suitable space-time formulations. The proposed makes mapping results non-Cartesian formulation fluid-structure interaction (FSI). demonstrated combining with strongly-coupled partitioned framework solving FSI problems. yields fully spline-based representation interface through single NURBS. coupling conditions at enforced Robin-Neumann type scheme. scheme particularly useful when considering incompressible fluids Dirichlet-bounded curved problems, as satisfies incompressibility constraint on each step procedure. accuracy performance introduced approach its coupled series two- benchmark