A comprehensive review on various approaches for performance improvement of Savonius wind turbines

The Savonius Vertical Axis Wind Turbine (VAWT) has gained significant attention as a wind energy solution due to its simple design, cost-effectiveness, and ability to perform well in urban and low-wind-speed environments. However, despite their advantages, these turbines face challenges, including lower efficiency compared to Horizontal Axis Wind Turbines (HAWTs) and performance limitations under high wind conditions. Therefore, this present review provides an in-depth examination of its design and aerodynamic performance, highlighting how various blade configurations and modifications, such as overlap ratios, helical blade structures, and hybrid designs, can enhance its efficiency. Additionally, key operational factors, such as tip speed ratio, Reynolds number, and turbulence effects, are explored in terms of their impact on power output. Different computational and experimental studies are also reported here, which address the influence of varying augmentation techniques. Moreover, the effects of different blade materials, artificial intelligence-based optimization, and innovative blade geometries are also investigated here to gain insight into several performance improvement approaches for Savonius turbines. Therefore, this present review can serve as a valuable resource for researchers and engineers working towards more efficient and sustainable Savonius wind turbines.