Computational Fluid‐Structure Interaction towards Simulating Large Wind Turbines with openFOAM and deal.II Coupled via preCICE

Abstract

Wind energy is an essential part of the Green Deal. The trend to increase the size of wind turbines, especially offshore, introduces additional dynamic effects at the long and flexible blades. Embedded in the CRC 1463, DFG, we are working on the fluid-structure interaction to avoid dynamic stall and investigate flutter effects and blade breathing of ultra-slim blades [1,2]. This requires an accurate numerical setup that reliably captures the fluid-structure interactions due to the highly turbulent flow and large deformations of the blades. In preliminary work, the Unsteady Reynolds-averaged Navier-Stokes method (URANS) in openFOAM [3] was used to simulate the flow around rotating helicopter blades with a changing angle of attack.[4] successfully predicted the distinct dynamic stall hysteresis with moderate computational effort and captured extreme values (load peaks) within the experimental uncertainties. This aerodynamic solver is to be coupled with a structural solution, for which deal. II [5] provides the linear elastic blade model. The fluid and the structure solvers are coupled via the software preCICE [6] and solved with a staggered approach. Numerical results are presented for a simplified 2D cross-section of a rectangular solid of carbon-fiber-reinforced polymers and a steady inflow velocity. Key challenges for the coupling of the solvers are discussed and the future work is outlined.