Aerodynamic optimization of the configuration of a pair of vertical axis wind turbines

This study optimized the layout of a pair of Darrieus vertical axis wind turbines through three-dimensional computational fluid dynamics (CFD) simulations. Three design parameters including the horizontal distance between the axes of two wind turbines (S), the vertical distance between the mid-heights of two wind turbines (h), and the orientation of two wind turbines with respect to the incoming wind (beta) were studied. A design of experiment method and a single objective optimization algorithm based on the Taguchi's method were employed to determine the optimum design parameters that maximize the power output of paired wind turbines. Analyzing the results showed that for all the numerical experiments, the power generation of paired wind turbines was more than that of a single wind turbine. In addition, it was realized that the vertical distance between the midheights of two wind turbines had the most influence and the horizontal distance between the axes of two wind turbines had the least impact on the average coefficient of power of paired wind turbines. The power output of paired wind turbines was maximum when wind turbines were placed at the same height and reduced significantly when there was a height difference. The power generation of paired wind turbines improved slightly by decreasing the horizontal distance between the axes of two wind turbines. The extent of impact of design parameters ordered as h > beta > S. The optimum values of the design parameters were determined to be beta = 90 degrees, h = 0, and S = 1.5 turbine diameters. Therefore, the power generation of paired wind turbines was maximum when wind turbines were placed side-by-side, at the same height, and at the smallest horizontal distance. It was revealed that for the optimum configuration, the power output of paired wind turbines improved by 26.60% with respect to that of a single wind turbine.