Cross-flow vortex induced vibrations of inclined helically straked circular cylinders: An experimental study

Zeinoddini, M.; Farhangmehr, A.; Seif, Mohammad Saeed; Zandi, A.P.

doi:10.1016/j.jfluidstructs.2015.09.005

Cited by 33 publications

(2 citation statements)

References 30 publications

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“…They concluded that the IP was shown to predict the vortex-shedding frequency reasonably well along the entire cylinder span for smaller yaw angles (less than 20 degrees), while the vortex-shedding in the wake becomes more disorderly. Zeinoddini et al [6] experimentally investigated the validity of the IP for cross-flow passing a yawed cylinder. It was reported that the IP is to some degree valid at low inclination angles, but the peak lift force was noticeably different from the prediction of the IP.…”

Section: Introductionmentioning

confidence: 99%

Effect of Lateral End Plates on Flow Crossing a Yawed Circular Cylinder

Liang

Duan

2019

Applied Sciences

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Numerical simulation is carried out to investigate the effect of the boundary condition of two lateral end-plate walls on the flow structure in the wake of a flow crossing a yawed circular cylinder. Two typical boundary conditions, nonslip and periodic, are investigated. It is revealed that the boundary condition of the two end-plates has a significant effect on the flow behaviors in the wake. Under the nonslip boundary condition, the vortex structure in the wake exhibits a tapering shape to the tip end. The flow pattern is formed in the wake as the streamlines on the tip side are becoming denser while the streamlines on the base end are becoming sparser. Spectral power analysis of the local lift coefficient shows that the frequency distribution exhibits axial variation. On the base side, the frequency distribution is broadband. On the tip side, there are two peak frequencies: the larger one corresponds to the value predicted by the independence principle, and the smaller one is generated by the secondary axial flow separation from the rear cylinder wall. Under the periodic condition, the numerical results show that organized Strouhal vortex is shed in the wake in the same way as to the flow orthogonally passing a cylinder and the independence principle is still applicable.

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Section: Introductionmentioning

confidence: 99%

Effect of Lateral End Plates on Flow Crossing a Yawed Circular Cylinder

Liang

Duan

2019

Applied Sciences

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“…One family of the commonly used add-on devices includes the helical strakes [4,5], shrouds [6,7], fairings [8] and splitters [9], which aims to mitigate the vortex induced vibration (VIV) by breaking the vortex shedding in the flow direction or changing the surface roughness and thus, reducing the drag coefficient and width of the lock-in region [10][11][12]. Although the effectiveness of these add-on devices have been proven by extensive studies and experiments, there still remains some shortcomings that limit their applications, including expensive machinery cost, difficulty in installation and susceptibleness to marine growth or storm damage [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of Seawater Exposure on Impact Damping Behavior of Viscoelastic Material of Pounding Tuned Mass Damper (PTMD)

Zhang

Patil

2019

Applied Sciences

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The pounding tuned mass damper (PTMD) is a novel vibration control device that can effectively mitigate the undesired vibration of subsea pipeline structures. Previous studies have verified that the PTMD is more effective and robust compared to the traditional tuned mass damper. However, the PTMD relies on a viscoelastic delimiter to dissipate energy through impact. The viscoelastic material can be corroded by the various chemical substances dissolved in the seawater, which means that there can be possible deterioration in its mechanical property and damping ability when it is exposed to seawater. Therefore, we aim to conduct an experimental study on the impact behavior and energy dissipation of the viscoelastic material submerged in seawater in this present paper. An experimental apparatus, which can generate and measure lateral impact, is designed and fabricated. A batch of viscoelastic tapes are submerged in seawater and samples will be taken out for impact tests every month. Pounding stiffness, hysteresis loops and energy dissipated per impact cycle are employed to characterize the impact behavior of the viscoelastic material. The experimental results suggest that the seawater has little influence on the behavior of the viscoelastic tapes. Even after continuous submersion in seawater for 5 years, the pounding stiffness and energy dissipation remains at the same level.

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