Laboratory measurements of vortex-induced vibrations of a vertical tension riser in a stepped current

Chaplin, J.R.; Bearman, P. W.; Huarte, F.J. Huera; Pattenden, R.J.

doi:10.1016/j.jfluidstructs.2005.04.010

Cited by 332 publications

(188 citation statements)

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“…Examples of typical experiments are free vibration of elastically mounted rigid cylinders (Feng, 1968;Vikestad, 1998;Govardhan and Williamson, 2000;Jauvtis and Williamson, 2004) and cylinders undergoing forced motions (Sarpkaya, 1978;Moe and Wu, 1990;Morse and Williamson, 2009;Aglen and Larsen, 2011;Yin and Larsen, 2012). Experiments with long flexible structures have also been performed, both under controlled laboratory conditions (Chaplin et al, 2005;Trim et al, 2005;HueraHuarte et al, 2014) and in more realistic field environments (Huse et al, 1998;Vandiver et al, 2006). These experiments focused on various flow situations such as uniform, sheared and stepped current, and in all cases the incoming flow was essentially stationary, i.e.…”

Section: Introductionmentioning

confidence: 99%

Time domain simulation of vortex-induced vibrations in stationary and oscillating flows

Thorsen

Sævik

Larsen

2016

Journal of Fluids and Structures

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This paper focuses on the further development of a previously published semi-empirical method for time domain simulation of vortex-induced vibrations (VIV). A new hydrodynamic damping formulation is given, and the necessary coefficients are found from experimental data. It is shown that the new model predicts the observed hydrodynamic damping in still water and for cross-flow oscillations in stationary incoming flow with high accuracy. Next, the excitation force model is optimized by simulating the VIV response of an elastic cylinder in a series of experiments with stationary flow. The optimization is performed by repeating the simulations until the best possible agreement with the experiments is found. The optimized model is then applied to simulate the cross-flow VIV of an elastic cylinder in oscillating flow, without introducing any changes to the hydrodynamic force modeling. By comparison with experiment, it is shown that the model predicts the frequency content, mode and amplitude of vibration with a high level of realism, and the amplitude modulations occurring at high Keulegan-Carpenter numbers are well captured. The model is also utilized to investigate the effect of increasing the maximum reduced velocity and the mass ratio of the elastic cylinder in oscillating flow. Simulations show that complex response patterns with multiple modes and frequencies appear when the maximum reduced velocity is increased. If, however, the mass ratio is increased by a factor of 5, a single mode dominates. This illustrates that, in oscillating flows, the mass ratio is important in determining the mode participation at high maximum reduced velocities.

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Section: Introductionmentioning

confidence: 99%

Time domain simulation of vortex-induced vibrations in stationary and oscillating flows

Thorsen

Sævik

Larsen

2016

Journal of Fluids and Structures

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“…The fundamentals of VIV have been well documented for a cylinder whose axis in quiescient fluid is perpendicular to the oncoming flow (normal incidence case), the body being either rigid and elastically-mounted (King et al 1973;Bearman 1984Bearman , 2011Naudascher 1987;Mittal & Tezduyar 1992;Hover et al 1998;Okajima et al 2002;Sarpkaya 2004;Williamson & Govardhan 2004;Klamo et al 2006;Leontini et al 2006;Benaroya & Gabbai 2008;Lucor & Triantafyllou 2008;Dahl et al 2010;Navrose & Mittal 2013;Cagney & Balabani 2014;Konstantinidis 2014) or flexible (Trim et al 2005;Chaplin et al 2005;Lie & Kaasen 2006;Lucor et al 2006;Huera-Huarte & Bearman 2009, 2014; Vandiver et al 2009;Modarres-Sadeghi et al 2011;Bourguet et al 2011aBourguet et al ,b, 2012Bourguet et al , 2013a. VIV naturally appear both in the cross-flow direction and in the in-line direction, i.e.…”

Section: Introductionmentioning

confidence: 99%

The onset of vortex-induced vibrations of a flexible cylinder at large inclination angle

Bourguet

Triantafyllou

2016

J. Fluid Mech.

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The onset of the vortex-induced vibration (VIV) regime of a flexible cylinder inclined at 80 • within a uniform current is studied by means of direct numerical simulations, at Reynolds number 500, based on the body diameter and inflow velocity magnitude. A range of values of the reduced velocity, defined as the inverse of the fundamental natural frequency, is examined in order to capture the emergence of the body responses and explore the concomitant reorganization of the flow and fluid forcing. Additional simulations at normal incidence confirm that the independence principle, which states that the system behavior is determined by the normal inflow component, does not apply at such large inclination angle. Contrary to the normal incidence case, the free vibrations of the inclined cylinder arise far from the Strouhal frequency, i.e. the vortex shedding frequency downstream of a fixed rigid cylinder. The trace of the stationary body wake is found to persist beyond the vibration onset: the flow may still exhibit an oblique component that relates to the slanted vortex shedding pattern observed in the absence of vibration. This flow component which occurs close to the Strouhal frequency, at a high and incommensurable frequency compared to the vibration frequency, is referred to as Strouhal component; it induces a high-frequency component in fluid forcing. The vibration onset is accompanied by the appearance of novel, low-frequency components of the flow and fluid forcing, which are synchronized with body motion. This second dominant flow component, referred to as lock-in component, is characterized by a parallel spatial pattern. The Strouhal and lock-in components of the flow coexist over a range of reduced velocities, with variable contributions, which results in a variety of mixed wake patterns. The transition from oblique to parallel vortex shedding, that occurs during the amplification of the structural responses, is driven by the opposite trends of these two component contributions: the decrease of the Strouhal component magnitude, associated with the progressive disappearance of the high-frequency force component, and simultaneously, the increase of the lock-in component magnitude, which dominates once the fully-developed VIV regime is reached and the flow dynamics is entirely governed by wake-body synchronization.

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“…Among these problems, VIV, which can be explained as the vibration stimulated by the external fluid flow vortices when interacting with the structure, is one of the critical design issue of the riser. Currently most of the investigations of the VIV of riser are conducted experimentally [1][2][3][4]. Nevertheless, due to the high cost in constructing the experimental facilities and large aspect ratio of the riser, several factors are usually being constrained in the model testing.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Vortex-Induced Vibration of Bare Cylinder and Cylinder Fitted with Helical Strakes

Lee¹,

Abu²,

Muhamad³

et al. 2017

MATEC Web Conf.

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Abstract. In the study, the vortex-induced vibration (VIV) of a cylinder fitted with and without helical strakes is investigated using fluid-structure interaction (FSI) software. The purpose is to predict the VIV characteristic of cylinder fitted with and without helical strakes. Fluid and structural solvers in commercial computational fluid dynamic (CFD) software were implemented as two-way FSI solvers to develop the simulation. A flexible circular cylinder of diameter, D = 0.018 m was tested. The pitch and height of the helical strakes were 10D and 0.10D, respectively. Existing experiment outputs of bare cylinder were used as benchmark to verify the simulated results. In overall, the simulation was able to predict the trend of the amplitude response and the mean drag coefficient. However, a slight over-prediction was noticed. It was also found that the helical strakes was able to reduce up to 60% of the VIV in water.

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Laboratory measurements of vortex-induced vibrations of a vertical tension riser in a stepped current

Cited by 332 publications

References 5 publications

Time domain simulation of vortex-induced vibrations in stationary and oscillating flows

Time domain simulation of vortex-induced vibrations in stationary and oscillating flows

The onset of vortex-induced vibrations of a flexible cylinder at large inclination angle

Prediction of Vortex-Induced Vibration of Bare Cylinder and Cylinder Fitted with Helical Strakes

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