*2.3. Wind Turbine Model*

The NREL 5 MW wind turbine was selected as the research object, which is a threebladed, upwind wind turbine and the power control adopts variable speed and variable pitch method. The diameter of the wind turbine is 126 m, and the hub height is 90 m. From root to tip, DU series airfoils of different thicknesses are used, and NACA series airfoils are used in the tip part. This study considers the existence of the tower, the bottom diameter of the tower is 6 m, and the top diameter is 3.87 m. The numerical simulation of the wind turbine is carried out under the rated operating conditions; the incoming wind speed is 11.4 m/s with the rotational speed of 12.1 r/min.
