Lidar Scanning of Induction Zone Wind Fields over Sloping Terrain

Scanning lidar instrumentation in the form of two synchronized ground-based WindScanners and a nacelle-mounted SpinnerLidar were deployed to measure wind fields in a vertical plane in the induction zone from 0.2 to 3 rotor diameters (D) in front of a Vestas V52 test turbine (D = 52 m) situated at DTU Risø Campus. First, the two ground-based WindScanners accurately reproduced the vertical profiles of horizontal mean wind speed when compared to measurements from a reference met-mast installed 2.2D upwind in the prevailing wind direction. The vertical plane scanned wind field measurements within in the induction zone were also compared with the vertical wind profiles measured at 1D by a nacelle-mounted scanning DTU SpinnerLidar. The vertical plane wind field as measured by the two ground-based WindScanners shows that the wind field in the induction zone is influenced by the turbine as well as by the slope of the terrain.