Vortex-induced vibrations and control of marine risers: A review

Hong, Keum‐Shik; Shah, Umer Hameed

doi:10.1016/j.oceaneng.2018.01.086

Cited by 163 publications

(29 citation statements)

References 190 publications

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“…It can be seen from the velocity vectors that resin flows from the two ends of the imprint roller. The vortices [22,23] show that resin slows down for some time and waits for the air to escape into the microcavities and, after escaping, the resin fills the microcavities. Figure 8 shows the incomplete filling at the rotating mold's high speed.…”

Section: Resultsmentioning

confidence: 99%

Numerical Study on the Optimization of Roll-to-Roll Ultraviolet Imprint Lithography

2019

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Roll-to-roll ultraviolet (R2R-UV) imprinting is a low-cost and high-throughput method that includes the manufacturing of large-area functional films. However, the quality of the final product is obstructed by the bubble entrapment during the imprinting process. In this study, a multi-phase volume of fluid (VOF) numerical model was used to remove bubble entrapment during the R2R imprinting process, which covered all parameters. This new modified numerical model with open-channel boundary conditions was based on the single zone that contains the direct contact of UV resin with the imprinting mold during the filling process. In addition, this model simulated the UV resin filling into microcavities at the preceding and succeeding ends of the imprinting mold. Different patterns of imprinting mold were considered to enhance the fidelity of R2R-UV imprinting for the comprehensive analysis. The experimental results validated through numerical simulations revealed that the bubble entrapment can be controlled by varying various parameters such as speed of the imprinting system, viscosity, contact angles, and pattern shape. The proposed model may be useful for a continuous bubble-free R2R imprinting process in industrial applications that includes flexible displays and micro/nano-optics.

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Section: Resultsmentioning

confidence: 99%

Numerical Study on the Optimization of Roll-to-Roll Ultraviolet Imprint Lithography

2019

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“…When the riser moves under the action of sea current, vortices are shed along its surface, resulting in the formation of an unstable wake region behind it. Vortex shedding normally takes place with different frequencies and amplitudes, thus induces a periodically varying transverse force on the riser (i.e., perpendicular to the direction of the current), resulting in a periodically transverse vibration known as the VIV [1][2][3][4]. Drilling and production risers are mostly affected by VIV, which leads to increases in their hydrodynamic loading and reduction in their service life due to fatigue.…”

Section: Introductionmentioning

confidence: 99%

Effect of Top Tension on Vortex-Induced Vibration of Deep-Sea Risers

Zhang

Guo

Tang

et al. 2020

JMSE

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With the increase of water depth, the design and use of the top-tensioned risers (TTR) are facing more and more challenges. This research presents the effect of top tension on dynamic behavior of deep-sea risers by means of numerical simulations and experiments. First, the governing equation of vortex-induced vibration (VIV) of TTR based on Euler-Bernoulli theory and Van der Pol wake-oscillator model was established, and the effect of top tension on natural vibration of TTR was discussed. Then, the dynamic response of TTR in shear current was calculated numerically by finite difference method. The displacement, bending stress and vibration frequency of TTR with the variation of top tension were investigated. Finally, a VIV experiment of a 5 m long flexible top-tensioned model was carried out at the towing tank of Tianjin University. The results show that the vibration displacement of TTR increases and the bending stress decreases as the top tension increases. The dominant frequency of VIV of TTR is controlled by the current velocity and is barely influenced by the top tension. With the increase of top tension, the natural frequency of TTR increases, the lower order modes are excited in the same current.

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“…It is widely accepted that accurately predicting the main features of the coupled in-line and cross-flow VIV response is the key to the engineering design of deep-water marine drilling risers. e detailed mechanism, related research methods, and some main features of the coupled in-line and cross-flow VIV response of long slender flexible cylinders have been described in some review literature [1,2].…”

Section: Introductionmentioning

confidence: 99%

Study on Vortex-Induced Vibration of Deep-Water Marine Drilling Risers in Linearly Sheared Flows in consideration of Changing Added Mass

Gao

Cong

Cui

et al. 2020

Mathematical Problems in Engineering

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In order to more accurately predict the coupled in-line and cross-flow vortex-induced vibration (VIV) response of deep-water marine drilling risers in linearly sheared flows, an improved three-dimensional time-domain coupled model based on van der Pol wake oscillator models was established in this paper. The impact of the in-line and cross-flow changing added mass coefficients was taken into account in the model. The finite element, Newmark-β, and Newton–Raphson methods were adopted to solve the coupled nonlinear partial differential equations. The entire numerical solution process was realized by a self-developed program based on MATLAB. Comparisons between the numerical calculations and the published experimental tests showed that the improved model can more accurately predict some main features of the coupled in-line and cross-flow VIV of long slender flexible risers in linearly sheared flows to some extent. The coupled in-line and cross-flow VIV of a real-size marine drilling riser, usually used in the deep-water oil/gas industry in the South China Sea, was analyzed. The influence of top tension force and seawater flow speed, as well as platform heave amplitude and frequency, on the riser in-line and cross-flow VIV was also discussed. The results show that the platform heave motion increases the VIV displacements and changes the magnitudes of peak frequencies as well as the components of frequencies. The platform heave motion also has a significant influence on the vibration modes of the middle and upper sections of the riser. The impact level of each factor on the in-line and cross-flow VIV response of the riser is different. The improved model and the results of this paper can be used as a reference for the engineering design of deep-water marine drilling risers.

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Vortex-induced vibrations and control of marine risers: A review

Cited by 163 publications

References 190 publications

Numerical Study on the Optimization of Roll-to-Roll Ultraviolet Imprint Lithography

Numerical Study on the Optimization of Roll-to-Roll Ultraviolet Imprint Lithography

Effect of Top Tension on Vortex-Induced Vibration of Deep-Sea Risers

Study on Vortex-Induced Vibration of Deep-Water Marine Drilling Risers in Linearly Sheared Flows in consideration of Changing Added Mass

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