Fluid-Structure Interaction: Simulation of a Tidal Current Turbine

Current trends in the development of new technologies for renewable energy systems show the importance of tidal and ocean current exploitation. But this also means to enter new fields of application and to develop new types of turbines. Latest measurements at economically interesting sites show strong fluctuations in flow and attack angles towards the turbine. In order to examine the dynamical behaviour of the long and thin structure of the turbine blades, coupled simulations considering fluid flow and structural behaviour need to be performed. For this purpose the parallel Navier-Stokes code FENFLOSS, developped at the IHS, is coupled with the commercial FEM-Code ABAQUS. Since the CFD domain has to be modelled in a certain way, the grid size tends to be in the range of about some million grid points. Hence, to solve the coupled problem in an acceptable timeframe the unsteady CFD calculations have to run on more than one CPU. Whereas, the structural grid is quite compact and, does not request that much computational power. Furthermore, the computational grid, distributed on different CPUs, has to be adapted after each deformation step. This also involves additional computational effort.