In a cluster of wind turbines, the interference between wind turbines affect negatively. Upstream wind turbines generate wakes where the velocity is reduced and the turbulence increased. A reduced power leads in lower efficiency and the high turbulence intensity generate fluctuating loads that creates fatigue problems. As a result, a fully understanding of the wake is needed in order to improve the wind turbines arrays.
Five models are investigated to predict the wake velocity decay and width development. Also, three models to describe the turbulence intensity are studied. Measurements from wind tunnel experiments are used to validate the models. The evaluation of the results shows that models can describe the behavior of the wake characteristics fairly well. The prediction of the velocity deficit as well as the width in the wake behind the turbine, are found to deviate with around only 3%
from the results, when the best analytical model is applied. More spread results are obtained regarding the turbulence intensity predictions, however, accurate results can be achieved. Thus, it can be concluded that analytical wake models are well suited to estimate the velocity deficit, width development, and the turbulence intensity in the far wake of a wind turbine.