Abstract
Savonius vertical axis wind turbines (VAWT) have advantages over horizontal axis wind turbines (HAWT), such as simple construction, acceptance of wind from any direction without orientation, self-starting, inexpensive etc. These advantages make it a viable proposition for small-scale applications in developing countries. In spite of the above advantages, VAWT are not gaining popularity mainly because of their poor efficiency. Hence, a three-bucket Savonius model rotor, having 8 cm bucket diameter and 20 cm height, was designed, fabricated, and tested in a sub-sonic wind tunnel. Provisions for variations of ‘blade’ overlap were included. Experiments were conducted for overlap conditions in the range of 16% to 35%. From the experimental investigations, power-coefficients (Cp) were calculated with and without blockage correction factors for tunnel interference. In both analyses, the power-coefficient increased if there was overlap, with an optimum value at 20% overlap of 47% without blockage correction, and 38% with blockage correction.