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The effect of externally applied rotational oscillations on FIV characteristics of tandem circular cylinders for different spacing ratios
Type Article
tandem cylinders, wake-induced vibration, rotary oscillation
In this study, an active control strategy for attenuation of in-line and transverse flow-induced vibration of two tandem-arranged circular cylinders is explored. The control system is based on the rotary oscillation of cylinders around their axis, which acts according to the lift coefficient feedback signal. The fluid-solid interaction simulations are performed for two velocity ratios (V_r=5.5 and 7.5), three spacing ratios (L⁄D=3.5,5.5 and 7.5) and three different control cases. Cases 1 and 2 respectively deal with the effect of rotary oscillation of front and rear cylinders, while case 3 considers the effect of applied rotary oscillation to both cylinders. The results show that in case 3, the flow-induced vibration of both cylinders is perfectly reduced, while in case 2, only the vibration of rear cylinder is mitigated and no change is observed in the vortex-induced vibration of front cylinder. In case 1, by rotary oscillation of the front cylinder, depending on the reduced velocity and the spacing ratio values, the transverse oscillation amplitude of the rear cylinder suppresses, remains unchanged and even increases under certain conditions. Hence, at every spacing ratio and reduced velocity, an independent controller system for each cylinder is necessary to guarantee a perfect vibration reduction of front and rear cylinders.
Researchers Amir Hossein Rabiee (First researcher) , Mostafa Esmaeili (Second researcher)