Computational Study of Savonius Wind Turbines

This work presents a computational study of a two-blade and a three-blade Savonius vertical axis wind turbines. The two-blade turbine was considered to be oriented at 0, 45, 90, and 135 degrees in reference to the direction of the prevailing wind. For the three-blade turbine, the orientations taken into account were 0, 30, 60, and 90 degrees in reference to the direction of the prevailing wind. The basic aim of this work was to study how the two designs are different from each other in terms of the forces acting on their blades. The computational simulations considered the turbines to be subjected to constant wind velocities of 5, 10, 20, and 30 m/s. Computational Fluid Dynamics (CFD) analyses were conducted for every case to find out the forces acting on the turbine blades for each orientation. All cases were run using “transition-SST” flow model and the turbine blades were meshed using ‘Quadrilateral Pave’ meshing scheme. Maximum change in pressure on the turbine blade occurs when the two-blade turbine is perpendicular to direction of the prevailing wind, i.e. at 90 degree. On the other hand, when three-blade turbine is at 60 degree orientation, maximum change is pressure occurs on the turbine blade. For the dimensions selected in this study (each blade having a radius of 0.3 m and height of 0.6 m) the maximum net forces on the two-blade turbine was calculated to be 298 N, while this value was 210 N on the three-blade turbine.