Abstract: In order to find out the Reynolds number effect on aerodynamic characteristics for generalized Savonius wind turbine (i.e., various types of Savonius wind turbine)and aerodynamic characteristics differences between conventional Savonius wind turbine and helical Savonius wind turbine with a twist of 180°, theoretical analysis and wind tunnel test are used to carry out the research. Based on the Reynolds number effect on drag coefficients of convex and concave, the aerodynamic characteristics of generalized Savonius wind turbine is almost independent of Reynolds number when the Reynolds number exceeds 10⁴. It is also inferred that the conventional Savonius wind turbine exhibits higher maximum averaged power coefficient than the helical one, by summing up the regularity of multi-staging effect. In order to testify the results of theoretical analysis, the conventional wind turbine and the helical one with the same aerodynamic shape with the rotation diameter of 360 mm, the height of 800 mm and the overlap of 100 mm are tested in low speed wind tunnel in Reynolds number range of 1.26×10⁵-2.21×10⁵. Moreover, the aerodynamic shapes effect and flow control of end plates on aerodynamic characteristics for the helical Savonius wind turbine also been are investigated, the experimental results indicate that both high aspect ratios of the wind turbine and the end plates could greatly increase the maximum averaged power coefficient and widen the range of tip speed ratios for relatively high power coefficient.

Key words: wind energy, helical Savonius wind turbine, Reynolds number, aerodynamic characteristics, flow control, wind tunnel test