- In this era of technological advancement, the demand for energy requirements is increasing globally. With a limited stock of fossil fuels and the pollution issue related to the burning of these fuels, the world needs to find an alternative of it, which must be cleaner and greener. This is where wind energy comes in and plays a vital role as it is a clean source and has a very promising future in the global energy sector. Savonius turbine is a type of vertical axis wind turbine (VAWT) which is predominantly rotated by the drag force from the wind. It is self starting and can extract wind energy from low wind speeds and is very practical to install it in crowded places due to its compact geometry. This thesis is a review of the previous works presented by different authors. This project aims at discovering the influence of various design and performance parameters (aspect ratio, overlap ratio, tip speed ratio, blade shape, number of rotor blades and number of stages), turbulence models and turbine geometries on the performance of Savonius vertical axis wind turbine. A conventional Savonius vertical axis wind turbine (VAWT) with aspect ratio of 1, overlap ratio of 0.15 and TSR of 0.8 shows the maximum coefficient of power (CP) The performance of conventional rotors can be enhanced by use of helical rotors; multi- staging and other modified blade geometries. Helical rotors with blade twist angle of 900 are better performing rotors than the conventional rotors. Modified Bach type rotor with a blade arc angle of 1350 , aspect ratio of 1.1, overlap ratio of 0.1 and at tip speed ratio (TSR)= 0.8 show the maximum coefficient of power (CP) of 0.30. The results of numerical analyses were compared with that of the experimental data and it is found that for 2-D numerical analyses, realizable k-ɛ turbulence model shows better accuracy of estimation and for 3-D analyses, SST k- ω turbulence model shows better agreement with the experimental data

Keywords : savonius wind turbine, wind energy, renewable energy, coefficient of power, tip speed ratio.