Harvesting wind energy for improving performance of Savonius rotor

In this work three methods of controlling the wind direction were aiming at improving the performance of Savonius rotor. The idea behind the new designs was to harvest the incoming wind to generate a wind jet to the concave side of the advanced blade and prevent the convex side of return blade from coming upwind stream. The prevented wind was guided in different designs to impinge the concave side of the return blade and hence to eliminate the negative torque and increase the exerted positive torque. The study could be numerically introduced using commercial Fluent-software. The SST k-omega turbulence model was used to simulate the turbulence behavior. The results showed that the suggested designs improve the performance of Savonius rotor in view of the power coefficient and the operation range. One of them enhanced the performance to reach a power-coefficient peak of 0.52 with operation range of tip speed ratio lambda <= 2.2. However, the new designs generated large wakes behind the rotor that must be considered in the turbines farm arrangement. (C) 2015 Elsevier Ltd. All rights reserved.