Comprehensive comparison of analytical wind turbine wake models with wind tunnel measurements and wake model application on performance modelling of a downstream turbine
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Wake effects in wind farms can cause significant power losses. In order to reduce these losses layout and control optimization can be applied. For this purpose, simple and fast tools to predict the wake flow are needed. In the first part of this work, six analytical wind turbine wake models are compared to extensive small-scale turbine wind tunnel measurements. The measurements are conducted at several downstream distances, varying the ambient turbulence intensity and the upstream turbine blade pitch angle. Furhermore, an adjustment of a recently developed wake model is proposed. Subsequently, the adjusted model is found to perform best throughout all test cases. In the second part, this wake model is used to predict the performance of a downstream turbine. In order to consider the non-uniform inflow velocity a mean-blade-element-velocity method is developed. Additionally, this method is compared to a simple method, which averages the velocity over the entire rotor area. Moreover, a Blade Element Momentum method with guaranteed convergence and blockage effect correction are applied. Finally, the simulations are compared to comprehensive wind tunnel measurements. In total, this approach is found to predict the wake velocity as well as the combined power of two aligned turbines fairly well.