LASER MEASUREMENTS OF WAKE DYNAMICS

For the first time ever instantaneous wakes deficits of wind turbines have been measured directly in two dimensions (2D). A laser Doppler system (Light Detecting And Rang-ing, LiDAR) is mounted on the back of the nacelle looking downwind. The 2D scanning feature is obtained combin-ing an optical modification of the LiDAR with a mechan-ical mechanism allowing for a rotation of the laser beam around a vertical axis.horizontal rotation, thus resulting in a horizontal sweep. The instrument is focused from one to ten rotor diameters downstream making it possible to study the meandering, shape, widening and attenuation of the wake deficit. Keywords: Remote sensing, LiDAR, wake