Numerical Study on the Vortex-induced Vibration of Circular Cylinder

In the vortex-induced vibration the structure interacts with the fluid flow that results in the vibration of the structure and sometimes leads to the destruction of it. In this paper, the effect of the vortex-induced vibration on one and two cylinder(s) in the rotating and non-rotating states are studied, numerically. For the case of single non-rotating cylinder, the effect of the reduced velocity and damping ratio on the displacement and velocity of circular cylinder and also on the lift coefficient and its components are investigated. The cylinder displacement decreases by increasing the damping ratio. The vortex shedding pattern for all examined reduced velocity and damping ratio is in the 2S mode. In all cases, two patterns of vibration, harmonic and beating phenomena, can be observed. The maximum value of the vibration amplitude is related to the reduced velocity of 4 for ζ= 0 and the minimum is belonged to the reduced velocity of 3. For the case of rotating cylinder, it is observed that the rotation of cylinder(s) affects the vortex shedding pattern and their strength, significantly. Therefore, the fluctuation of lift coefficient and vibration of cylinder(s) are reduced considerably.