Numerical Investigations of Upwind and Downwind NREL 5MW Reference Wind Turbines Using CFD and CSD

The aerodynamic and structural behavior of four wind turbine configurations based off of the model NREL 5MW offshore horizontal axis wind turbine (HAWT) are examined using Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD) models. The four configurations studied were three-bladed, upwind and downwind, and two-bladed upwind and downwind configurations. In the CFD analysis, effects of pure aerodynamic loads on the wind turbine are studied. Rotor performance, such as power, full or sectional torque and bending moments of rotor blades, tower aerodynamic loading, and wake impact behind the rotor are compared and investigated. These high fidelity airloads are used as input to the CSD code in order to compute the system response to the applied airloads. The current CFD and CSD analyses provide insight into performance and aeromechanical responses of the offshore horizontal axis wind turbines.