Comparison of wake tracking methods applied to full-scale measurements of wind turbine wakes in interactions
A scanning Lidar measurement campaign had been performed from 2015 Nov. to May 2016 in a wind farm located in Picardie, France, and composed of seven wind turbines (Enercon MM82), in order to capture the wakes of two wind turbines in interactions. A statistical analysis of the database had been carried out and published. It provided wind turbine wake trajectory, velocity deficit and meandering intensity, depending on the level of interactions between both wakes. Some unexpected outcomes were sometimes obtained when the level of interactions were high. For instance, the upstream wake is as attracted by the induction zone of the downstream wind turbine. Additionally, the wake centrelines were not perfectly aligned with the ensemble averaged wind direction. These results are not intuitive and might be due to the wake tracking method used in the data processing.
Consequently, the sensitivity of wake statistics to the wake tracking method will be presented. Results obtained with methods based on the velocity and momentum deficits and on Gaussian function fit is discussed.