Higher demand for energy has lead to increase in the consumption of conventional energy which has become more expensive and scarce. There is the need to generate power from renewable sources to reduce the demand for fossil fuels and growing concern due to increase in the effects of climate change, such as global warming and acid rain generated by extensive and deliberate use of fossil fuels in the electric generating plants and transport system. In this work, the aerodynamic characteristics of Savonius wind turbine were investigated numerically by varying the rotor configuration (semi-circular and segment of circle) and overlap ratio so as to obtain the optimum design configuration which could give better performance of Savonius rotor. Comparison between the static torque coefficient at different overlap ratios of 0%, 20%, and 40% for the two configurations were studied using Solidworks CFD software. The flow around the rotor with overlap ratio variation was analyzed with the help of velocity, pressure contours and static torque coefficient equation of the rotor. It was observed from the analysis that the overlap of 20% was the optimum overlap condition at which pressure, velocity differences and coefficient of static torque across the rotor were the highest for both configurations and that segment of a circle produced the highest characteristics for better performance. Keywords: Overlap ratio, aerodynamic, Savonius, Static torque coefficient, rotor configuration
