Modeling and analysis of a fully passive swinging sail wind turbine

Abstract

AbstractWind energy has been an attractive renewable energy source, and in recent decades, highly efficient horizontal axis wind turbines have been developed and successfully deployed. However, alternative designs for wind energy conversion have also been proposed. In previous studies, a novel swing sail design for wind energy harvesting was proposed and analyzed. This turbine harvests energy by pitching a sail, causing a mast to swing, which in turn drives a flywheel in a rectified rotational motion. The rotating flywheel is then used to drive an electric generator. The designed turbine was originally semiactive, while in the present study, the fully passive version of the turbine was proposed, and its performance was examined. The turbine consists of an oscillating sail attached to a reciprocally moving mast via a torsion spring, and the wind‐driven oscillatory motion is transformed into the rotational motion of a flywheel using a ratchet. Furthermore, a dry‐friction dynamometer was utilized as a simple way of extracting energy. The dynamical equations of the turbine were derived and were used to analyze the time response of the turbine. In the model, the correlations for the aerodynamic lift and drag forces for a flat plate were utilized. The results were validated using the computation fluid dynamics (CFD) simulation. The effects of various dynamical and geometric parameters of the turbine on the generated power and the turbine performance were also investigated.