A Basic Research on the VIV Response of Rotating Circular Cylinder in Flow

The characteristics of VIV response of rotating circular cylinders in flow had been investigated by both experiment and numerical simulation. In the experiment, the motions of a flexible circular cylinder pipe installed in a circulation water channel were measured. In simulation, a Discrete Vortex Method had been used to estimate hydrodynamic forces acting on a rigid circular cylinder. When a cylinder rotates in flow, a rotation frequency becomes important added to natural frequency and vortex shedding frequency. The deflection of a flexble pipe peaked when the frequency ratio of rotation frequency to natural frequency was between 1.0 and 1.5. This is similar to increment of oscillation amplitude by a resonance of natural vibration and vortex shedding. The peak oscillation frequency of a rotating circular cylinder in flow decreased with increase in rotation number. The main axis of cylinder oscillation turned in the rotation direction.