Wind turbine power extraction under partial wake operations, a CFD study using ALM.

Abstract

This study focuses on the intricate interplay between large wind turbines and their wake effects on neighboring turbines. We specifically investigate the influence in power production and aerodynamic loads when a turbine operates under the influence of upstream turbine wakes. The analysis has been performed by means of Computational Fluid Dynamic simulations using OpenFOAM, while wind turbines are modelled with an Actuator Line Model approach. Two large IEA 15 MW reference wind turbines, with one turbine partially affected by the other’s wake, are analyzed. The research assesses the influence of turbine spacing on aerodynamic torque and blade loads. The study shows that the CP may suffer oscillations 2 orders of magnitude greater than the ones observed at the reference cases. For the most affected case, the torque experiences oscillations of a 5.46 % w.r.t. to the averaged torque over the last ten revolutions. The influence of operating in partial wake conditions is specially relevant on the blade root loads that are found to suffer an increase of ∼ 20 % and a decrease of ∼ 30 % over one revolution as the blade is affected by the highly sheared flow resulting from the upstream wake.