Varying VAWT Cluster Configuration and the Effect on Individual Rotor and Overall Cluster Performance

The effect of separation distance between turbines on overall cluster performance were simulated using computational fluid dynamics software and we found that at a distance equivalent to two rotors, there was an improvement of +8.06% in the average performance of the cluster compared to a single, isolated turbine. A very small improvement in performance was noted at the equivalent distance of 12 rotor diameters. The performances of three individual turbines in pyramid- and inverted pyramid-shaped vertical axis wind turbine clustered farm configurations with varying oblique angles at a fixed spacing of two equivalent rotor diameters were also investigated. The design experiment involves the simulation of test cases with oblique angles from 15 degrees to 165 degrees at an interval of 15 degrees and the turbines were allowed to rotate through 18 full rotations. The results show that the left and right turbines increase in performance as the angle with respect to the streamline axis increases, with the exception of the 165 degrees angle. The center turbine, meanwhile, attained its maximum performance at a 45 degrees oblique angle. The maximum cluster performance was found to be in the configuration where the turbines were oriented in a line (i.e., side by side) and perpendicular to the free-stream wind velocity, exhibiting an overall performance improvement of 9.78% compared to the isolated turbine. Other array configurations show improvements ranging from 6.58% to 9.57% compared to the isolated turbine, except in the extreme cases of 15 degrees and 165 degrees, where a decrease in the cluster performance was noted due to blockage induced by the left and right turbines, and the center turbines, respectively.

Automated summary

Using computational fluid dynamics software, the study found that the distance between turbines affects overall cluster performance, with variations in performance observed at different oblique angles in pyramid- and inverted pyramid-shaped vertical axis wind turbine configurations. The study also showed that turbines oriented in a line and perpendicular to the free-stream wind velocity exhibited the highest cluster performance improvement.