A reduced order, partitioned fluid-structure interaction (FSI) solver is developed to assess the importance of blade flexibility on the performance of a 5 MW wind turbine in the presence of atmospheric boundary layer (ABL) turbulence. The temporally and spatially varying wind conditions due to the ABL cause fluctuations in the aerodynamic forces and moments of the rotor blades. Analyzing the effect of blade flexibility on the estimated aerodynamic loading and power output is the primary objective of this project.
The FSI solver implemented in this work follows a partitioned approach that incorporates an existing OpenFOAM-based actuator line method (ALM) solver and a modal structural dynamics (SD) solver. This reduced-order solver incorporates a tightly coupled framework using a fixed-point iteration to ensure proper convergence of the flow field and structural displacements at each time step. Simulations using uniform flow are first performed to verify the solver’s functionality, and to evaluate the solver’s coupling characteristics for such things as the importance of blade bend-twist coupling, the effect of aerodynamic pitching moment, and the need for tight coupling.
