Influence of a passive upstream deflector on the performance of the Savonius wind turbine

Some recent studies show that the aerodynamic efficiency of the Savonius wind turbine can be improved by adding a properly designed deflector upstream of the rotor blade. However, these deflector designs can only improve the turbine efficiency in specific flow directions, which causes the loss of omnidirectionality. In this paper, a passive deflector is designed to solve this problem. The passive deflector can passively adjust its position with the change in wind direction so that the efficiency of the Savonius rotor is improved regardless of wind directions. For the sake of investigating the aerodynamic performance of the Savonius rotor with the new deflector, three-dimensional computational fluid dynamics simulations are performed at different operating conditions. The CFD method uses a set of high-quality structured grids and is validated with existing empirical data. The results show that the passive deflector can obtain a stable orientation adaptively according to the wind direction, and the maximum efficiency of the classical Savonius rotor is increased by 24.91% using the passive deflector. (c) 2022 The Authors. Published by Elsevier Ltd.