Experimental Investigation of Wind Turbine Wakes in the Wind Tunnel

Detailed wake measurements with two similar model wind turbines, with a diameter of 0.9m, were performed in the wind tunnel. A single turbine arrangement and a tandem setup, where a wind turbine was operated in the wake of an upstream wind turbine, were tested. Measurements of the cross section in the near and far wake as well as measurements in axial direction are presented. A single hot-wire and a five-hole probe were used. The application of the five-hole probe enabled to measure a three-dimensional flow field providing detailed inspections of the rotation of the wake. A strong tower wake and a non-uniform velocity field and turbulence distribution were observed.