PIV investigation of flow past a rotating circular cylinder

Abstract

In the present study, the effects of rotating a circular cylinder on the vortex shedding are investigated by Particle Image Velocimetry measurement. The experiments were conducted for flow past a circular cylinder of aspect ratio 25 in a recirculating water channel at Reynolds numbers in the range of 200 to 1000. The rotational to translational speed ratio α varies from 0 to 5. The present results show the existence of a critical α value in the range of 2 to 3, above which the vortex shedding is suppressed as reported in the literature. The critical α appears to decrease with increase in flow Reynolds number. Below this critical α, the Kármán vortex street is observed. When α increases, both flow separation positions move in the direction of cylinder rotation; and vortex shedding is increasingly deflected towards the rotation direction of the cylinder. Above the critical α, vortex shedding disappears, and a closed streamline is formed around the cylinder. At higher α, only counter clockwise (same direction as cylinder rotation) vorticity was observed around the cylinder. Through this investigation, it is hoped that we can better understand the effects of cylinder rotation on the flow past a slender circular cylinder. © 2010 SPIE.