Fluid-structure interaction on Cartesian grids: Flow simulation and coupling environment

Despite their frequently supposed problems concerning the approximation of complicated and changing geometries, hierarchical Cartesian grids such as those defined by spacetrees have proven to be advantageous in many simulation scenarios. Probably their most important advantage is the simple, efficient, and flexible interface they offer and which allows for an elegant embedding of numerical simulations in some broader context, as it is encountered in a partitioned solution approach to coupled or multi-physics problems in general and to fluid-structure interaction in particular. For the latter, a flow solver, a structural solver, and a tool or library performing the data exchange and algorithmic interplay are required. Here, the main challenge still unsolved is to keep the balance between flexibility concerning the concrete codes used on the one hand and overall efficiency or performance on the other hand. This contribution addresses two of the above-mentioned modules of a partitioned approach to FSI - the coupling environment and the flow solver, focusing on a strictly Cartesian, hierarchical grid. We report the design, implementation, and tuning of both and present first steps towards FSI simulations.