Turbulence ahead

Although the wind may blow smoothly onto a wind turbine, it comes out the other end shredded into a complex collage of whorls, large and small. In a wind farm, the turbulent wake generated by the first row of turbines drives the turbines in the next rows, which produce up to 40% less power and suffer more from bumpier winds. Researchers are developing tools to improve the overall efficiency of wind farms. "One important factor for designing a wind farm is its layout, or how the turbines are positioned relative to each other," says Yu-Ting Wu, a PhD student at EPFL. In one of the recently published papers, Wu compared results from a numerical simulation of the wind through a wind farm to wind tunnel experiments, focusing specifically on where the turbines are placed within in the wind farm. Wind farms have often been set up along a square grid. Wu's simulations show that simply changing the wind farm's layout can increase the total efficiency of the wind farm by giving the turbulent wake flow more time to recover before it reaches the next turbine.