A study of the near wake structure of a wind turbine comparing measurements from laboratory and full-scale experiments

Wake flow measurements have been performed using the technique of particle image velocimetry (PIV) at stations downstream from a model wind turbine rotor, and evaluated against experimental data from two full-scale machines. Comparisons include both mean velocity and turbulent intensity cross-wake profiles at a range of tip speed ratios. The application of PIV to the study of wind turbine wakes is described in detail, including the steps required to ensure appropriate and accurate simulation of the flow field conditions. The results suggest that the PIV method is a potentially useful tool in the investigation of detailed wake how, though significant differences are observed between wake velocity deficits at full- and model scale. These are discussed with regard to scale effect, the influence of terrain, model similarity, and the phenomenon of wake meandering and effective cross-wake smoothing. Copyright (C) 1996 Elsevier Science Ltd.