A Fundamental Study on Momentum Propagation and Turbulence Characteristics around a Rotating Cylinder

- Turbulence Characteristics around a Rotating Cylinder without Unform Flow and with High Rotation Ratio -

Abstract

　In this study, tank experiments and computational fluid dynamics (CFD) calculations were conducted to clarify the effect of flow on the momentum transfer characteristics to the flow field around a rotating circular cylinder in still water, and were compared for high rotation ratios.In the tank experiments, the results resembled the velocity profile around a rotating cylinder in still water in the range of rotation ratios above 15, showing a tendency for the lift coefficient to decrease while the drag coefficient remained constant. At even higher rotation ratios, the lift-drag ratio is expected to continue to decrease while approaching more closely that of a rotating cylinder in still water. Numerical calculations reproduced the velocity profile in the tank experiment under still water conditions. However, the surface friction coefficient was different between the value estimated from the velocity profile and the value estimated from the wall shear stress in the tank experiment. Numerical calculations for high rotation ratios were very similar to the velocity profiles in still water at a higher rotation ratio of about 140.