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Numerical Investigation on Severe Slugging in A Catenary Riser

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China Ocean Engineering 2019年第5期33卷 628-635页

作者： QI Xiao-liang GAO Song guo hai-yan College of Engineering Ocean University of China Qingdao 266100 China Marine Design & Research Institute of China Shanghai 200240 China

A mathematical model is presented to study the main characteristics of severe slugging in a downward inclined pipeline followed by a catenary riser. In this model, both simplified transient model and phase distribution model are included so that the flow characteristics of each stage for severe slugging can be accurately reproduced, especially for blowout stage. The results show that the flow features of severe slugging can be simulated by the proposed mathematical model. A good agreement between the experimental data and the numerical results is observed. The model can predict the transient fluctuation of many respects, such as the superficial gas velocity at the bottom of the riser and the average velocity at the outlet of the riser.

关键词： severe slugging pipeline-riser system phase distribution transient fluctuation

Experimental Study on Vortex-Induced Vibration Coupling Wake Interference of Multi-Riser Groups with Sensitive Spacing

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China Ocean Engineering 2022年第3期36卷 333-347页

作者： WANG Yu LI Peng LIU Yu CHEN Xin LOU Min guo hai-yan College of Architecture and Civil Engineering Shandong University of Science and TechnologyQingdao 266590China Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Qingdao 266590China School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China College of engineering Ocean University of ChinaQingdao 266100China

The“riser group−fluid between risers”is taken as the carrier,and the experiment on vortex-induced vibration of tandem riser groups coupling interference effect under sensitive spacing is *** least-square method is used to linearly fit the reduced velocity and main frequency,and the rule of Strouhal numbers is *** mode is separated based on the mode decomposition theory,and the mode conversion mechanism is also *** concept of“interference efficiency”is introduced to study the dynamic characteristics and response evolutions of different riser *** results show that the wake shielding effect widely exists in tandem riser groups,and the interference effect of midstream and downstream risers on their upstream risers is significantly lower than that of upstream risers on midstream and downstream *** trajectories of midstream and downstream risers lag behind their upstream risers due to multiple shadowing effects,the vibration frequency range of downstream riser is widened and the dominant frequency is extremely *** with the isolated riser,wake interference suppresses the vibration dis-placement of the midstream and downstream risers in the in-line direction,and enhances the displacement of upstream and midstream risers in the cross-flow *** interference effect of the fluid between risers at low velocities is stronger than that at higher velocities,and the cross-flow displacements of upstream risers are always in the interference enhancement *** is urgent to pay attention to the cross-flow displacement of upstream and midstream risers in tandem riser groups considering the safety design.

关键词： vortex-induced vibration interference effect multi-riser groups sensitive spacing tandem arrangement dynamic response

Experimental Study and Fatigue Analysis of Vortex-Induced Vibration of Umbilical Cable Considering Internal Friction

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China Ocean Engineering 2020年第2期34卷 151-161页

作者： GU Hong-lu guo hai-yan LIU Zhen LI Fu-heng AN Wan-bo LI Peng College of Engineering Ocean University of ChinaQingdao 266100China College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China

In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses,the experimental study on VIV of bond umbilical cable(BUC)and un-bond umbilical cable(UBUC)was carried out in an experimental tank.A current generator in the laboratory simulated the uniform current,and the current velocities were observed in real time by using a Doppler *** addition,different sizes of top tension were applied to the umbilical cable *** VIV responses of the umbilical cable model were measured by using Fiber Bragg grating(FBG)strain *** displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition *** this paper,the traveling wave characteristics,the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are *** experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of *** UBUC appears the traveling wave sooner than BUC,but its standing wave characteristics are more obvious than those of BUC at high *** with BUC,the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner,but has narrower bandwidth in the"lock-in"*** level of fatigue damage of BUC was approximately the same as that of UBUC.

关键词： internal friction umbilical cable vortex-induced vibration traveling wave fatigue damage

An Experimental Study on Dynamics Features of Three Side-by-Side Flexible Risers Undergoing Vortex-Induced Vibrations in A Uniform Flow

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China Ocean Engineering 2020年第4期34卷 500-512页

作者： LIU Yu LI Peng WANG Yu LIU Li-hua WANG Fei guo hai-yan FU Qiang College of Architecture and Civil Engineering Shandong University of Science and TechnologyQingdao 266590China Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Qingdao 266590China College of engineering Ocean University of ChinaQingdao 266100China yantai China International Marine Containers Raffles Offshore Ltd Yantai 264000China

A vortex-induced vibration(VIV)experiment on three side-by-side risers subjected to a uniform flow was carried out in a combined wave-current *** dynamic features of interference effect on three side-by-side risers were investigated by varying fluid velocity and inter-riser *** distributions of dimensionless displacement,dominant frequency,and displacement trajectory of the model risers were measured using mode decomposition and wavelet transform *** coupled interference of inter-riser fluid to adjacent risers at different spacings was disclosed by introducing the"interference ratio"*** results show that at spacings smaller than 6.0 D,the three model risers display appreciable deviations in their displacement responses in cross-flow or in-line direction,attributable to the strong proximity disturbance and wake interference between the *** the spacing is increased to 8.0 D,wake interference still makes great difference to the dynamic response of the risers in both *** reduced velocity increases,the three risers show higher agreement with an isolated riser in overall dominant vibration frequency in CF direction than that in IL direction at all spacings and the side risers,although symmetrically placed,do not vibrate symmetrically,as a result of the steady deflection of clearance flow within the riser *** effect results in a remarkable unsteady mode competition within the risers;quantitation of the interference levels for the three risers at different spacings with interference ratio revealed that under low flow velocities and large spacing ratios,clearance flow constitutes a non-neglectable interferer for three side-by-side risers.

关键词： three-riser group VIV side-by-side arrangement interference effect clearance flow mode competition

Experimental Investigation of Disturbing the Flow Field on the Vortex-Induced Vibration of Deepwater Riser Fitted with Gas Jetting Active Vibration Suppression Device

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China Ocean Engineering 2020年第3期34卷 341-351页

作者： LI Peng JIANG Zhen-xing LIU Yu WANG Yu guo hai-yan WANG Fei ZHANG Yong-bo College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Qingdao 266590China College of Engineering Ocean University of ChinaQingdao 266100China National Oceanographic Center of Qingdao Qingdao 266071China

An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined *** vibration suppression device was designed in which the jet pipe was horizontally fixed to the front end of the *** varying three different excitation spacings and multi-stage outflow velocities,the influence law of the dominant frequency,dimensionless displacement and other dynamic response parameters was studied under different excitation spacings,and the mechanism and sensitive characteristics of the disturbance suppression were *** results indicate that the variation of excitation spacing makes gas curtain enter the strong disturbed flow region at different velocities and angles,and the coupling relationship between excitation spacing and reduced velocity is the key factor to enter the strong disturbed flow region to achieve the optimal disturbance *** the strong disturbed flow region,the influence of gas curtain on the dominant frequency is obviously affected by the flow velocity,while the vibration displacement is stable at the same amplitude and is weakly affected by the flow *** curtain can effectively disturb the formation of vortex shedding,destroy the strong nonlinear coupled vibration of the riser,and achieve better vibration suppression *** the weak disturbed flow region,the vortex length of the riser tail is prolonged,the strong nonlinear coupled vibration of the riser is gradually restored,and the vibration suppression effect of the device gradually decreases.

关键词： deepwater riser vortex-induced vibration(VIV) active vibration suppression jet-type excitation spacing disturbance flow

Experimental Study on Vortex-Induced Vibration of Rough Risers Coupling with Interference Effect in Tandem Arrangement

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China Ocean Engineering 2024年第3期38卷 394-407页

作者： HU Ze-bo LIU Zhen LI Peng guo hai-yan REN Xiao-hui HOU Hao HAO Lian-hong College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine Civil Engineering Materials and Structures Qingdao 266590China College of Engineering Ocean University of ChinaQingdao 266100China

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined *** experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the *** rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged *** experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity *** the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced *** the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’*** the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

关键词： marine riser vortex-induced vibration tandem arrangement roughness interference effect

Experimental Study on Vortex-Induced Vibration of Rough Risers with Coupling Interference Effect Under Side-by-Side Arrangement

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China Ocean Engineering 2024年第1期38卷 18-28页

作者： HU Ze-bo LIU Zhen LI Peng guo hai-yan WANG Shu-bing REN Xiao-hui HOU Hao WANG Ye-shuo College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine Civil Engineering Materials and Structures Qingdao 266590China College of Engineering Ocean University of ChinaQingdao 266100China CHEC Dredging Co. LtdShanghai 200136China

A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined *** roughness of the riser was characterized by arranging different specifications of surface attachments on the surface of the *** risers with three different roughnesses were arranged side by side with smooth risers to explore the VIV response of the riser under the combined action of roughness and interference effect,and to reveal the coupling mechanism between roughness and interference *** experimental results show that,compared with that of a smooth riser,the VIV of a rough riser under the coupling interference effect has a wider"lock-in"region,and the displacement decreases more significantly at a high reduced velocity,which is more likely to excite higher-order modes and frequency *** addition,the displacement response and frequency response of the smooth riser are not significantly affected by wake interference from the rough riser,which is caused by the decrease of the wake region due to the delay of the boundary layer separation point of the rough riser.

关键词： marine riser vortex-induced vibration side-by-side arrangement roughness interference effect

Laboratory Measurements of Vortex- and Wake-Induced Vibrations of A Tandem Arrangement of Two Flexible Risers

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China Ocean Engineering 2016年第1期30卷 47-56页

作者：刘怀增王飞蒋国盛郭海燕李效民 Faculty of Engineering China University of Geosciences Wuhan 430074 China College of Engineering Ocean University of China Qingdao 266100 China

The dynamic response of two flexible model risers in tandem arrangement immersed in a stepped current was analyzed. The risers, with an external diameter of 20 mm and a total length of 6200 mm, had an aspect ratio of 310. They were hinged to the support structure at the center-to-center distances away 3-12 times the external diameter. The top 1200 mm was exposed to a uniform current at a speed which was up to 0.9 m/s（the Reynolds number was 18000） and the rest in still water. The dynamic responses, which were obtained through the Fiber Bragg Grating strain gauges mounted on the surface, were analyzed by studying the cross-flow amplitudes and modal weights. The cross-flow vibration were observed up to the third mode, and the modal transformation from the second mode to the third mode was clearly observed. The experiment confirmed that the typical vortex-induced vibration（VIV） had occurred on the up-stream riser. But for the down-stream riser, the main excitation mechanism was wake-induced vibration（WIV）. The modal transformation of WIV was more complex than that of VIV, which might be helpful for other researchers to study the interference effect.

关键词： marine riser vortex-induced vibration tandem arrangement

两自由度不同截面形式柱体涡激振动的CFD数值模拟

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船舶力学 2016年第5期20卷 530-539页

作者：赵婧郭海燕中国海洋大学工程学院山东青岛266100

文章采用计算流体力学(CFD)方法,结合SST k-ω湍流模型,对低质量比柱体进行两自由度涡激振动数值模拟,得到了柱体升力、曳力系数的时程曲线,并观察了柱体进入锁振状态的幅值变化,研究了不同截面形式柱体在外流速处于0.1-1.0 m/s范围内... 详细信息

文章采用计算流体力学(CFD)方法,结合SST k-ω湍流模型,对低质量比柱体进行两自由度涡激振动数值模拟,得到了柱体升力、曳力系数的时程曲线,并观察了柱体进入锁振状态的幅值变化,研究了不同截面形式柱体在外流速处于0.1-1.0 m/s范围内的振动响应。将圆柱体在不同流速下两向振动的CFD数值模拟与实验数据进行比较,得到了较为满意的结果。通过分析不同截面柱体在不同外流速下的振动幅值发现,带有抑振装置的柱体截面形式能够有效地减小涡激振动,其中,板状截面柱体抑振效果较好。

关键词：涡激振动计算流体力学两自由度抑振