Effect of traveling wave on the vortex-induced vibration of a long flexible pipe

2019 ◽  
Vol 84 ◽  
pp. 122-132 ◽  
Author(s):  
Zheng-Shou Chen ◽  
Shin Hyung Rhee
Keyword(s):  
Traveling Wave ◽  
Flexible Pipe ◽  
Vortex Induced Vibration

Flexible Spools Solution for Hybrid Risers Base for Green Fields Developments

2015 ◽  
Author(s):  
S. Tarbadar ◽  
S. Legeay ◽  
M. Bonnissel ◽  
O. Nossa ◽  
A. Karnikian
Keyword(s):  
Soil Properties ◽  
Deep Water ◽  
Oil Fields ◽  
Direct Connection ◽  
Flexible Pipe ◽  
Vortex Induced Vibration ◽  
Single Top ◽  
Dynamic Loadings ◽  
Operating Constraints ◽  
Steep Wave

Rigid spools are commonly used at the riser base of hybrid riser systems such as STTRs (Single Top Tensioned Risers) or BHORs (Bundle Hybrid Offset Risers) for the deep water oil fields. Rigid spools design is critical and governed by numerous operating constraints such as dynamic loadings (due to motion of the vertical riser, Vortex Induced Vibration, slugging, etc.), soil properties and soil/spools/structures interaction. Recent surveys on existing brown fields have highlighted unexpected issues on existing rigid spools. To solve these issues, an innovative flexible spool solution has been developed, combining unbonded flexible pipe structures in a “steep wave” configuration to accommodate the riser motions and FLET (Flowline End Termination) excursions avoiding soil deterioration and preventing unexpected spool behavior which could ultimately jeopardize its integrity. A steep wave configuration solution can be introduced with distributed buoyancy over the flexible spools length. This design allows a direct connection between the riser base assembly and the flowline termination, solving the embedment issue and easing accommodation of the hybrid riser motions. This paper describes the recent issues with rigid spools design and describes the solutions developed with flexible spool configurations to provide a more reliable riser base spools system for green fields.

Flow control on the vortex-induced vibration of a circular cylinder using a traveling wave wall method

2018 ◽  
Vol 21 (11) ◽  
pp. 1664-1675 ◽  
Author(s):  
Feng Xu ◽  
Wei-feng Bai ◽  
Wen-li Chen ◽  
Yi-qing Xiao ◽  
Jin-ping Ou
Keyword(s):  
Circular Cylinder ◽  
Flow Control ◽  
Traveling Wave ◽  
Vortex Induced Vibration ◽  
Wall Method

scholarly journals The analysis of vortex induced vibration of the flexible pipe in a cylindrical fluid field with cross flow

2016 ◽  
Vol 18 (4) ◽  
pp. 2403-2417
Author(s):  
Qian-Bei Yue ◽  
Ju-Bao Liu ◽  
Ri-Zhi Dong ◽  
Qiang Zhang
Keyword(s):  
Cross Flow ◽  
Flexible Pipe ◽  
Vortex Induced Vibration ◽  
Fluid Field

scholarly journals The Effect of Exposure Length on Vortex Induced Vibration of Flexible Cylinders

2012 ◽  
Author(s):  
Zhibiao Rao ◽  
J. Kim Vandiver ◽  
Vikas Jhingran ◽  
Octavio Sequeiros
Keyword(s):  
Strouhal Number ◽  
Model Test ◽  
Traveling Wave ◽  
Practical Problem ◽  
Recent Model ◽  
Response Frequency ◽  
Vortex Induced Vibration ◽  
Pipe Model ◽  
Exploration And Production ◽  
Exposure Length

This paper addresses a practical problem: “What portion of fairing or strake coverage may be lost or damaged, before the operator must take corrective measures?” This paper explores the effect of lost fairings (the exposure length) on Vortex-Induced Vibration (VIV) of flexible cylinders. The source of data is a recent model test, conducted by SHELL Exploration and Production. A 38m long pipe model with varying amounts of fairings was tested. Response as a function of percent exposure length is reported. Unexpected results are also reported: (i) the flexible ribbon fairings used in the experiment did not suppress VIV at speeds above 1 m/s; (ii) Above 1 m/s, a competition was observed between VIV excited in the faired and bare regions of the cylinder, (iii) Unusual traveling wave behavior was documented—waves generated in the bare region periodically changed direction, and exhibited variation in VIV response frequency. The results of these tests showed that (1) the excitation on the bare and faired regions could be identified by frequency, because the faired region exhibited a much lower Strouhal number; (2) as expected, the response to VIV on the bare region increased with exposure length; (3) the response to VIV on the faired region decreased with exposure length.

Drag and added mass coefficients of a flexible pipe undergoing vortex-induced vibration in an oscillatory flow

2020 ◽  
Vol 210 ◽  
pp. 107541
Author(s):  
Haojie Ren ◽  
Mengmeng Zhang ◽  
Yifan Wang ◽  
Yuwang Xu ◽  
Shixiao Fu ◽  
...  
Keyword(s):  
Oscillatory Flow ◽  
Added Mass ◽  
Flexible Pipe ◽  
Vortex Induced Vibration

scholarly journals Cross-Flow Vortex-Induced Vibration (VIV) Responses and Hydrodynamic Forces of a Long Flexible and Low Mass Ratio Pipe

2019 ◽  
Vol 7 (6) ◽  
pp. 179 ◽  
Author(s):  
Xifeng Gao ◽  
Zengwei Xu ◽  
Wanhai Xu ◽  
Ming He
Keyword(s):  
Critical Mass ◽  
Cross Flow ◽  
Dominant Frequency ◽  
Hydrodynamic Forces ◽  
Dynamic Responses ◽  
Mass Ratio ◽  
Flexible Pipe ◽  
Force Coefficient ◽  
Vortex Induced Vibration ◽  
Low Mass

Laboratory tests were carried out to investigate the cross-flow (CF) dynamic responses and hydrodynamic forces of a flexible pipe that subjected to vortex-induced vibration (VIV). The pipe had a critical mass ratio of 0.54 and an aspect ratio of 181.8. The uniform flow environment was realized by towing the pipe along a towing tank. The towing velocity ranged from 0.1–1.0 m/s with an interval of 0.05 m/s. Two axial pre-tension cases (200 N and 300 N) were enforced. The structural strains were measured at seven positions evenly distributed along the pipe. Then a modal analysis method was applied to reconstruct the displacement responses. It is revealed that the maximum CF displacement amplitude reached up to 2.18 pipe diameter and the strain response exhibited higher harmonic components. The CF dominant frequency gradually rises with the increase of reduced velocity and up to a three-order vibration mode can be observed. In addition, mean drag coefficient, lift force coefficient and added mass coefficient were also calculated to further investigate the fluid force feature of a low mass flexible pipe undergoing VIV.

scholarly journals Experimental Investigation on Vortex-Induced Vibration of a Flexible Pipe under Higher Mode in an Oscillatory Flow

2020 ◽  
Vol 8 (6) ◽  
pp. 408 ◽  
Author(s):  
Haojie Ren ◽  
Mengmeng Zhang ◽  
Jingyun Cheng ◽  
Peimin Cao ◽  
Yuwang Xu ◽  
...  
Keyword(s):  
Oscillatory Flow ◽  
Cross Flow ◽  
Dominant Frequency ◽  
Ocean Basin ◽  
Dominant Mode ◽  
Flexible Pipe ◽  
Vortex Induced Vibration ◽  
Displacement Reconstruction ◽  
Vessel Motion ◽  
Lock In

Different from the previous studies of the vortex-induced vibration (VIV) dominated by first mode of flexible pipe in an oscillatory flow, the features of a higher mode dominated are experimentally investigated in the ocean basin. The flexible pipe is forced to harmonically oscillate with different combinations of a period and amplitude. The design dominant mode consists of first and second modes under the maximum reduced velocity (VR) of approximately 5.5 with a KC number ranging from 22 to 165. The VIV responses between only the excited first mode and the excited higher mode are compared and studied using displacement reconstruction and wavelet transform methods. The discrepancies of spatial and temporal response between smaller and larger KC numbers (KC = 56 and 121) are first observed. The strong alternate mode dominance and lock-in phenomena occur in the case of larger KC numbers, while they cannot be observed in the case of smaller KC numbers under higher modes. The VIV dominant frequency in the in-line (IL) direction is found to be always triple the oscillatory flow frequency and not twice that in the cross flow (CF) direction. The dominant frequency in the CF direction can be predicted by the Strouhal law, and the Strouhal number is approximately 0.18 under VR = 5.5, which is not affected by the excited mode. Moreover, differences of response motion trajectory are also revealed in this paper. The present work improves the basic understanding of vessel motion induced VIV and provides helpful references for developing prediction methods of VIV in an oscillatory flow.

Vortex-induced vibration of flexible pipe fitted with helical strakes in oscillatory flow

2019 ◽  
Vol 189 ◽  
pp. 106274 ◽  
Author(s):  
Haojie Ren ◽  
Yuwang Xu ◽  
Jingyun Cheng ◽  
Peimin Cao ◽  
Mengmeng Zhang ◽  
...  
Keyword(s):  
Oscillatory Flow ◽  
Flexible Pipe ◽  
Vortex Induced Vibration ◽  
Helical Strakes
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