Experimental and numerical studies on the wake behavior of a horizontal axis wind turbine

• Presents full scale measurements of wind turbine wakes using Sodar and Lidar.
• Numerical analysis was performed using full rotor modeling.
• Good agreement is obtained between the experimental and the numerical results.
• A 60% reduction in power is seen up to 5D downstream of the turbine.

The wake characteristics of a horizontal axis wind turbine have been investigated, both experimentally and numerically. The computational numerical solution was carried out for the full rotor model, using a Navier–Stokes solver, employing the k–ε model appropriately modified for the atmospheric flows. The experiments were conducted at a 2 MW wind turbine for the measurements of upstream wind speed profiles, using SOund Detection and Ranging (SODAR), and wake wind speed profiles using Light Detection and Ranging (LIDAR), at varying distances between 2 and 7 times the rotor diameters downstream of the wind turbine. The evaluation of the computational model is made by comparing the predicted and measured velocities at the prescribed downstream locations at different upstream wind speeds. The present numerical setup employing the k–ε model and the fully mesh resolved rotor shows good agreement with the measurements. The model is used to find the relation between the wind speed and the wake recovery.