Effect of Coriolis force on a wind farm wake

Srinidhi Nagarada Gadde,Richard J.A.M. Stevens

doi:10.1088/1742-6596/1256/1/012026

Abstract

The effect of the Coriolis force on the wake of a wind farm in a conventionally neutral and a stable boundary layer is investigated using large eddy simulations. We find that the average flow angle varies with the downstream position in the wind farm. In the entrance region of the wind farm, the flow blockage and wind veer create a positive gradient of the vertical flux at hub-height, which causes a counter-clockwise flow deflection in the Northern hemisphere, when observed from above. Further downstream, the vertical entrainment of air from the upper layers of the boundary layer generates a negative gradient of the vertical flux at hub-height, which results in a clockwise flow deflection in the Northern hemisphere. The deflection is more pronounced for the stable boundary layer than for the conventionally neutral boundary layer. In addition, we find that the wake deflection has a significant impact on the power production of turbines further downstream in the wind farm.

Highlights

The ever increasing demand for clean energy has led to a growing focus on the development of wind farms
We find that the average wind angle varies with downstream position in the wind farm
Flow blockage and wind veer create a positive gradient flux at hub-height in the entrance region of the wind farm, which results in a counter-clockwise flow deflection

Summary

Introduction

The ever increasing demand for clean energy has led to a growing focus on the development of wind farms. Abkar and Porte-Agel [5] performed LES of a wind turbine in a stable boundary layer (SBL) and found that the wind turbine wakes at hub-height are deflected in clockwise direction and are skewed due to the strong wind veer. They reasoned that the Coriolis force turns the wind farm wake clockwise in the Northern Hemisphere due to the entrainment of fresh momentum from upper layers of the boundary layer.

Results

Conclusion