Effects of spacing between wind turbines on blade dynamic stall

Abstract

The article presents the results of the application of an analytical model to determine the regions of a tandem wind turbine blade, operating in the wake of an upstream wind turbine, affected by dynamic stall. The wind conditions used as the input for the model were determined based on the Large Eddy Simulation of the turbine wake. The dynamic stall occurrence on the tandem wind turbine blade was studied as a function of the spacing between the wind turbines. It was observed that, even with an ambient turbulence intensity of 0.5% for the upstream wind turbine, approximately 30% of the tandem wind turbine blade was under the influence of dynamic stall for spacing up to at least 20 turbine diameters. The main causes of dynamic stall on the tandem wind turbine blade were shown to be the increased turbulence intensity in the turbine wake and the large rate of change of yaw angle experienced by the tandem wind turbine operating in the wake of the upstream turbine.