Numerical investigation on the suppression of VIV for a circular cylinder by three small control rods. (March 2017)

• Record Type: Journal Article
• Authors: Song, Zhenhua; Duan, Menglan; Gu, Jijun
• Is Part Of: Applied ocean research. Volume 64(2017)
• Page Start: 169
• Page End: 183
• Publication Date: 2017-03
• Subjects: Laminar flow -- VIV suppression -- Control rods -- CFD -- FSI; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2017.03.001
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: The efficacy of VIV suppression is excellent while the attack is larger than the critical angle. Phase closely relates to the reduction of transverse displacement amplitude of the circular cylinder with 3 control rods. Two symmetrical configurations ( α = 0º and α = 60º) result in totally different symmetrical vibration trajectories. The frequencies of vibration of the main cylinder with 3 control rods are generally smaller than that of an isolated cylinder. 2 rods in behind of the main cylinder perform more efficient than that of 1 rod in front for VIV suppression as the gap ratio of G/D less than 1.0. Abstract: Laminar flow past a circular cylinder with 3 small control rods is investigated by numerical simulation. This study is concerned with the suppression efficacy of vortex induced vibration by small control rods located around a main cylinder. The effects of the attack angle and rod-to-cylinder gap ratio on the hydrodynamics and vibration responses of the main cylinder are investigated. The attack angle of α = 45° is performed as the critical angle for VIV suppression of 3 control rods. The 3 control rods have no effect on VIV suppression when the attack angle is less than the critical angle. The 3 control rods have an excellent VIV suppression efficacy when the attack angle is larger than the critical angle. The transverse vibration frequency of the cylinder with 3 control rods is less than that for an isolated cylinder for all the configurations. The numerical results for the configurations of α = 45° & 60°, G / D = 0.6–1.2 show excellent suppression efficient among the cases investigated in this study. The best suppression efficient is found at α = 45°, G / D = 0.9 for 3 control rods. 2 rods in behind of the main cylinder perform more efficient than that of 1 rod in front for VIV suppression as the gap ratio of G / D less than 1.0.