2D and 3D numerical simulation of the wind-rotor/nacelle interaction in an atmospheric boundary layer

Two-dimensional axisymmetric and three-dimensional steady turbulent flow computations around two horizontal-axis wind turbines (Nordex N80 and Jeumont J48) are carried out to investigate the wind-rotor/nacelle interaction and quantify its effects on the wind speed at the nacelle anemometry. The actuator disk concept has been used to model the action of the blades. For both turbines, the geometry of the nacelle was reproduced as faithfully as possible. The terrain was represented by an appropriate law of the wall to account for roughness with particular attention paid to the boundary conditions in order to reproduce the neutral atmospheric boundary layer. The calculated velocity field in the vicinity of the nacelle exhibits good agreement with available experimental data. The results also show that for a complex nacelle geometry, like that of the N80, a three-dimensional calculation is necessary to obtain a good prediction of the velocity field in the near wake. The hub height effect is evaluated for the J48 by raising the nacelle from a height of 36 to 60 m. No significant impact is noted on the ratio nacelle wind speed/freestream wind speed.