Experimental characterization of wind turbine wakes: Wind tunnel tests and wind LiDAR measurements

The characterization of wind turbine wakes produced for different loading conditions of the turbine and incoming wind is a crucial task for design of wind farm layout. Indeed, the optimization of the power harvested from a wind farm can only be achieved if detrimental wake interactions are carefully inhibited or mitigated. In this paper the importance of performing wind turbine wake measurements is emphasized through two experiments, which are complementary for the experimental measurement techniques used and scientific results achieved. First, wind tunnel tests of a down-scaled wind turbine are presented, for which fixed-point turbulence measurements are leveraged to predict the hub vortex instability encountered in the near wake. The second experiment consists in wind LiDAR measurements of the wake produced by a utility-scale wind turbine under different regimes of the atmospheric thermal stability. It is shown that wind turbine wakes recover faster under convective conditions than for neutral ones. Published by Elsevier Ltd.