Investigating the factors affecting the performance of Savonius wind turbine

Nowadays, wind energy is considered one of the cleanest sources of energy, and the capacity of wind power plants is growing around the world. In particular, the design and construction of small wind turbines have been the subject of much research. This article deals with the Savonius wind turbine, a well-known vertical axis turbine. First, the mechanical principles of operation of this type of wind turbine are explained. Then, the criteria for determining its efficiency and performance, such as power and torque coefficients, are stated. The sequel discusses the geometric and technical factors affecting its efficiency. These factors include the overlap ratio, number of blades, number of stages, twist angle, shaft diameter, and the installation of end plates. The current paper can be helpful for those trying to improve the performance of this type of turbine. In this regard, there are some proposed innovative designs to enhance the performance of the Savonius turbine concerning experimental results and their numerical simulations. These designs increase the maximum power coefficient to 38%, although they complicate the turbine structure. Some of these innovative designs are also reviewed.