A numerical method for fluid-structure interactions of slender rods in turbulent flow

This thesis presents a numerical method for the simulation offluid-structure interaction (FSI) problems on high-performancecomputers. The proposed method is specifically tailored tointeractions between Newtonian fluids and a large number ofslender viscoelastic structures, the latter being modeled asCosserat rods. From a numerical point of view, such kind ofFSI requires special techniques to reach numerical stability.When using a partitioned fluid-structure coupling approachthis is usually achieved by an iterative procedure, whichdrastically increases the computational effort. In the presentwork, an alternative coupling approach is developed basedon an immersed boundary method (IBM). It is unconditionallystable and exempt from any global iteration between the fluidpart and the structure part.The proposed FSI solver is employed to simulate the flowover a dense layer of vegetation elements, usually designatedas canopy flow. The abstracted canopy model used in thesimulation consists of 800 strip-shaped blades, which is thelargest canopy-resolving simulation of this type done so far.To gain a deeper understanding of the physics of aquaticcanopy flows the simulation data obtained are analyzed, e.g.,concerning the existence and shape of coherent structures.