The effect of spanwise wavy blade on performance enhancement of a small vertical axis wind turbine was investigated in this study. The SST k-ω turbulence model was utilized to solve the three-dimensional numerical model of a wind turbine with different wavy blades. The results indicated that the straight blade with optimized spanwise wavy configuration could greatly improve the aerodynamic performance of wind turbine. The power coefficient was sensitive to the length and amplitude of the wavy configuration. The results demonstrated that the wavy blade could be used as an effective solution to alleviate the dynamic stall effect of wind turbine.
Wind turbine is considered as an efficient device to convert sustainable wind energy into electricity to meet the growing power demands. It is supposed that the floating vertical axis wind turbine (VAWT) would show a lot of advantages as it serves on land. Compared to the traditional horizontal axis wind turbine (HAWT), however, the relative low power efficiency of the VAWT has hindered its further development. On the other hand, the modification of blade configuration is regarded as an effective way to improve the performance of wind turbine.
Compared with the traditional H-type VAWT or Φ-type VAWT, some VAWT structures proposed in recent years were proven to have better aerodynamic performance. Some project progress and details about a novel V-shaped wind turbine rotor were reported by Parsons, Chatterton, Brennan, and Kolios in 2011. This wind turbine was designed specifically for the offshore wind conversion, and compared with the original one, it would reduce the greenhouse gas emissions by about 20%. Scheurich and Brown (2013) compared the aerodynamic performances of helical twisted blade, troposkein-shaped blade, and straight blade. The helical VAWT was proven to have a higher power coefficient when the blade curvature and helical twist angle were optimized. Hilewit, Matida, Fereidooni, Abo, and Nitzsche (2019) redesigned the traditional Φ-type VAWT. Both the height and frontal area of turbine blade were decreased and shifted to form a shiftedtroposkein shape VAWT. The results showed that the modified wind turbine could effectively improve the power coefficient at high tip speed ratios, and the material cost was saved by reducing the blade size and weight. Besides, the concept of V-shaped blades was recently proposed to improve the power output of VAWT by Su, Chen, Han, Zhou, Bao, and Zhao (2020). It was found that in addition to the enhancement in the power coefficient, the V-shaped blade was able to alleviate the damage caused by lateral loads to the wind turbine.