Analysis the vortex effect on the performance of Savonius windmill based on CFD simulation and video recording

Abstract

Savonius windmill is ideal for areas that have low wind speeds and fluctuating. However, the weakness of Savonius windmill is the efficiency or better known as the coefficient of performance (Cp) is lower than horizontal axis wind turbine and Darrieus wind turbines. One cause is the formation of vortex when the blade was rotating. Vortex will absorb the energy of the wind flow or cause a negative kinetic energy. CFD simulation can be used as one tool that can be used to help analyze the loss of wind flow, including the formation of vortex on Savonius blades. Wind speed of 2 m/s and 5 m/s is used as a simulation variable to obtain an overview of wind flow losses occurring in blade Savonius. The largest vortex formed at an angle of 165 o rotating blade is good for wind speed of 2 m/s and 5 m/s. The larger the vortex area are formed causing the lower the pressure and torque acting on the blade surface.