Effect of additional cylinders on power-extraction performance of a Savonius vertical-axis wind turbine

To improve the power-extraction performance of the Savonius vertical-axis wind turbine (S-VAWT), additional cylinders, which are used to control the fluid flow around the wind turbine blade, were introduced into the blade design. In contrast to the traditional numerical method, a mathematical model in the form of a dynamical system was used in this study. A numerical calculation program that could effectively solve the equations of wind-induced rotation of S-VAWT was developed, and combined with the Taguchi experimental method to investigate the influence of additional cylinders on the power-extraction characteristics of the S-VAWT. The results showed that the additional cylinders have a significant impact on the power-extraction performance of the S-VAWT. At 4-m/s wind speed, the average power coefficient of the S-VAWT with additional cylinders is 15% higher than that of the conventional S-VAWT. After construction of the wind turbine prototype and power-extraction tests, the results showed that compared with a conventional S-VAWT, the output power was 29% higher for the S-VAWT with additional cylinders under the same particular conditions.