Pressure measurements and flow visualization study of a Savonius rotor

Abstract The power mechanism of a Savonius rotor has been studied by pressure measurements on the blade surface and by a flow visualization experiment. It is found that a low pressure region is formed on the convex side of the advancing blade contributing to the power production of the rotating rotor. This phenomenon is observed as a Coanda-like flow pattern in the flow visualization experiment, which controls the flow separation on the convex side. It is also noticed that the flow field near the rotor is effectively two-dimensional as the torque and the power coefficients evaluated from the pressure measurements at the middle plane agree closely with the results by total torque measurement.