Experimental investigation of slug flow-induced vibration of a flexible riser

Zhu, Hongjun; Gao, Yue; Zhao, Hongbo

doi:10.1016/j.oceaneng.2019.106370

Cited by 44 publications

(14 citation statements)

References 18 publications

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“…6), an increasing trend is revealed from C3 to C5 as Lu/d increases. A similar experimental observation was also reported in Zhu et al [12]. Such a correlation may be owing to the enhanced imbalance in the flow state at higher RGL, potentially leading to the greater slug flow-induced loads.…”

Section: Resultssupporting

confidence: 87%

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Experiment on the Effect of Superficial Gas-Liquid Velocities on Slug Flow-Induced Vibration in an Inclined Sagged Riser

Ma¹,

Srinil²,

Zhu³

et al. 2021

Preprint

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Subsea liquid-gas flows conveyed through a flexible riser or pipeline may develop into various flow patterns including slug flow. In this study, the slug flow-induced vibration (SIV) of an inclined sagged riser conveying upward air-water flows is experimentally investigated. A small-scale experiment is carried out in an air-water test loop with a section of a freehanging catenary tube made of silica gel. Attention is placed on the effect of superficial gas and liquid velocities on SIV responses. Both pipe motions and flow patterns are recorded using non-intrusive high-speed cameras. Pressure variations are also measured at the pipe inlet and outlet by two pressure transducers. The SIV system is tested by employing different ratios of the superficial gas-liquid velocities. Occurrence of unstable slug flows is captured at the relatively high gas-toliquid velocity ratios, leading to a large-amplitude SIV. Experimental results of the space-time varying riser responses and oscillation frequencies are reported together with the associated slug flow features. Depending on the gas-liquid superficial velocities, slug flow characteristics are observed to vary significantly. These entail an intermittent SIV with modulated amplitudes and frequencies along riser span, signalling a potential dynamic stress and fatigue-related concern. In all experimental cases, the riser responses are found to be multi-modal and dominated by the fundamental planar mode whereas an out-of-plane vibration is negligible. Experimental observations suggest the key interrelationships of the two-fluid flow conditions, the slug characteristics and the pipe dynamics. This finding is meaningful for a practical design of riser transporting internal multiphase flows.

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Section: Resultssupporting

confidence: 87%

“…Recently, SIV of curved pipes has been experimentally studied by Zhu et al [12] who observed slug flow-induced planar vibrations and a resonant frequency between the pipe and the internal pressure fluctuation. They remarked the strong dependence of SIV on the ratios of gas-liquid flow rates and the associated liquid slug lengths.…”

Section: Introductionmentioning

confidence: 99%

Experiment on the Effect of Superficial Gas-Liquid Velocities on Slug Flow-Induced Vibration in an Inclined Sagged Riser

Ma¹,

Srinil²,

Zhu³

et al. 2021

Preprint

Self Cite

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“…The in-plane SIV is dominated by the fundamental mode in the gas-liquid flow rate ratio range of 0.5-1.827. When increasing this flow rate ratio to 3.031, a travelling wave characteristic of the fundamental mode dominates the inplane response (Zhu et al, 2019a). Three slugging flow regimes have been observed over a wide flow rate range.…”

Section: Introductionmentioning

confidence: 91%

“…The vibration displacement of each marker is extracted by comparing its position from adjacent images, and the slug length is obtained by scaling the pixels occupied by the slug to the actual size. One can refer to our previous works for the image post-processing method and the precision examination test (Zhu et al, 2019a(Zhu et al, , 2019b.…”

Section: Non-intrusive Measurement and Processingmentioning

confidence: 99%

Mode switching and standing-travelling waves in slug flow-induced vibration of catenary riser

Zhu

Gao

Srinil

et al. 2021

Journal of Petroleum Science and Engineering

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“…Turbulence within flowing fluid, especially two-phase flows, may results in fluid-induced excitation. Among various flow regimes, slug flow is notorious to cause fluid-induced vibration (FIV) due to its oscillating changes in pressures and phase change hence resulting in a variation of piping amplitudes [1]. In addition, experimental and numerical investigations on dynamic behaviour of slug flow in a horizontal piping system were performed by Wang et al [2].…”

Section: Introductionmentioning

confidence: 99%

Effects of Selection of Inlet Perturbations, Multiphase and Turbulence Equations on Slug Flow Characteristics Using Altair® AcuSolve™

et al. 2021

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Selection of inlet perturbations, multiphase equations, and the turbulence equation may affect the development of slug flow using computational fluid dynamic simulation tools. The inlet perturbation, such as sinusoidal and random perturbations, play an essential role in inducing slug formation. Multiphase equations such as volume of fluid and level set methods are used to track and capture the gas-liquid immiscible interface. Similarly, turbulence equations such as Spalart Allmaras (SA), Detached Eddy Simulations (DES), k-omega, and k-epsilon can be used to predict the evolution of turbulence within the flow. At present, no direct comparison is available in the literature on the selection of (i) types of inlet perturbations, (ii) the choice of multiphase equations, and (iii) the turbulence equation on the development of slug flow using the Altair computational package. This article aims to compare the effects of the selection of inlet perturbations, multiphase models and turbulence equations on slug flow characteristics using Altair® AcuSolve™. The findings by Altair® simulation were compared to published experimental data and simulation works using ANSYS and STAR-CCM+. The slug flow characteristics of interest include slug morphology, a body length-to-diameter ratio, velocity, frequency, and pressure gradient. It was found that the slug flow could be developed for all combinations of settings. Although level set approach in Altair® can track fluid motion successfully, it has a limitation in modelling the convective transport of the multiphase mixture well, unlike ANSYS and STAR-CCM+. Compared to the standard level set method, the coupling of back-and-forth error compensation and correction with the level set function helps to capture the internal boundary more accurately by reducing errors caused by numerical diffusion in the transport of the level set. It was revealed that the Spalart Allmaras turbulence equation could mimic published experimental result better than DES as it produced the closest slug translational velocity. Since the frequency of the slugs for the developed models showed a good agreement with the published data, the models could be sufficient for the investigation of fluid-structure interaction.

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Experimental investigation of slug flow-induced vibration of a flexible riser

Cited by 44 publications

References 18 publications

Experiment on the Effect of Superficial Gas-Liquid Velocities on Slug Flow-Induced Vibration in an Inclined Sagged Riser

Experiment on the Effect of Superficial Gas-Liquid Velocities on Slug Flow-Induced Vibration in an Inclined Sagged Riser

Mode switching and standing-travelling waves in slug flow-induced vibration of catenary riser

Effects of Selection of Inlet Perturbations, Multiphase and Turbulence Equations on Slug Flow Characteristics Using Altair® AcuSolve™

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