Abstract
Flow fields around a Savonius rotor with and without a rotation are studied by flowvisualization experiment with the smoke-wire method. In case of the rotating rotor, the tip speed ratio is set at the maximum power performance. Based on the variations of the flow-pattern with and without a rotation, and with a rotor angle, the effect of the rotor rotaion is discussed in ralation to its power performance. It is found that at small rotor angles Coanda like flows are formed on the convex side of an advancing rotor, and as the angle increases large circulating vortices are shed downstream from both the sides of the rotor. Such Coanda like flows prompt a rotor rotation though the vortices act inversely.
