An incompressible immersed boundary solver for moving body flows using a cut cell discontinuous Galerkin method

•A high-order sharp interface immersed boundary method for moving domain problems is proposed.•The main advantage is the significant decrease in total degrees of freedom in comparison with similar methods.•The calculation of hydrodynamic forces is done by using hierarchical moment fitting quadrature.•The fluid and body part of the solver are explicitly coupled.

We present a higher-order immersed boundary method (IBM) for moving body flows, based on a discontinuous Galerkin (DG) discretization. In our method bodies are represented by a sharp interface approach using cut cells. The position of the bodies and their velocity is prescribed by Newtons equation of motion. Furthermore, we introduce a splitting type approach of coupling fluid and rigid body solver and point out the explicit calculation of hydrodynamic forces using hierarchical moment fitting. To verify our method we compare our new approach to a range of numerical benchmarks taken from the literature. At first we compare our method with calculations using a body fitted grid. Thereafter we will focus on representing boundaries with fixed motion to point out the accuracy and flexibility of our IBM. Afterwards we show results of full coupled test cases in which the explicit coupling approach and the calculation of forces mentioned above come into play. It can be shown, that with our method we can get similar results by decreasing the number of total unknowns significantly, which is the main advantage of the proposed scheme.