Large eddy simulation study of extended wind farms with large inter turbine spacing

Abstract

Abstract We study the performance of extended wind farms with very large inter turbine spacings, i.e. with an inter turbine spacing of more than 10 turbine diameters, using large-eddy simulations (LES) for the special case of neutral conditions. We compare the results with predictions from different analytical modeling approaches and discuss in which parameter regimes the different model predictions agree with the LES predictions. We find in LES that the normalized power output variance increases further downstream in the wind farm. Besides, we analyze the power output correlation between the subsequent downstream turbines. We find that the correlations decrease with increasing turbine spacing due to the increased mixing induced by the wind turbine wakes. For all cases considered here, the power output correlation with downstream turbines becomes negligible after about 40 turbine diameters.