scholarly journals Experimental investigation on the dynamic responses of a free-hanging water intake riser under vessel motion

2016 ◽  
Vol 50 ◽  
pp. 1-19 ◽  
Author(s):  
Jungao Wang ◽  
Sherry Xiang ◽  
Shixiao Fu ◽  
Peimin Cao ◽  
Jianmin Yang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Water Intake ◽  
Dynamic Responses ◽  
Vessel Motion

Dynamic analysis of a suspended pump in a vertical well connected to the ocean

1983 ◽  
Vol 10 (3) ◽  
pp. 481-491 ◽  
Author(s):  
Bassem M. Eid ◽  
Sheldon H. Zemell
Keyword(s):  
Complex System ◽  
Dynamic Analysis ◽  
Water Intake ◽  
Hydrodynamic Force ◽  
Salt Water ◽  
Vertical Wall ◽  
Dynamic Responses ◽  
Water Level Fluctuations ◽  
Wave System ◽  
Structural Dynamic

In the design of a salt-water intake system which is connected to the ocean, a numerical model is developed to simulate the hydraulic and structural dynamic responses to the ocean's wave action. On the basis of available data, the design wave height is determined from the condition for breaking. For such a complex system, wherein several natural periods are contributing to the total response, a range of wave periods is considered. The standing wave system resulting from the reflection of a progressive wave train from a vertical wall (clapotis) is modelled and the hydrodynamic response of the system is computed. To limit water level fluctuations in the well, a strong damping of the water column is provided by constricting the flow through an orifice plate installed at the bottom of the pump well. The hydrodynamic force on the suspended pumps due to nearby submerged turbulent jet flow is described. A damped single-degree-of-freedom oscillator is employed to represent the structural dynamics of the pumps. Extensive experiments are required to supplement this work in order to describe the complex system fully. Keywords: dynamic analysis, salt-water intake, waves, hydrodynamic force, suspended pump, submerged jet, oscillator.

Intake shape and boundary-related considerations in the operation and design of storm-sewer drop structures

2009 ◽  
Vol 36 (11) ◽  
pp. 1825-1834 ◽  
Author(s):  
A. Auckland ◽  
I. Nistor ◽  
R. Townsend
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Water Intake ◽  
Experimental Work ◽  
Vortex Formation ◽  
Design Guidelines ◽  
Hydraulic Efficiency ◽  
Local Shape ◽  
Geometrical Characteristics ◽  
Storm Sewer

This paper presents the results of an experimental investigation into the hydraulic efficiency of a vertically oriented water intake. Under low submergence conditions, the operation of such an intake is affected significantly by the formation of surface vortices, which result in significant flow reduction and the downstream entrainment of air and swirl. The experimental work considered the fact that vortex formation is governed by the geometrical characteristics of the intake, including the diameter, local shape, submergence, surrounding boundary, etc, and the velocity distribution in the approaching flow. Therefore, an experimental study was conducted to investigate the influence that the local shape and the proximity to nearby boundaries have on the hydraulic performance of a vertical water intake. The results of this experimental investigation will hopefully lead to a better understanding of the phenomena governing the flow in such structures and to the elaboration of improved engineering design guidelines.

Water Intake Riser Model Test and Numerical Calibration

2015 ◽  
Author(s):  
Sherry Xiang ◽  
Peimin Cao ◽  
Jingxi He ◽  
Steve Kibbee ◽  
Sean Bian
Keyword(s):  
Water Flow ◽  
Water Intake ◽  
Model Test ◽  
Large Diameter ◽  
Internal Flow ◽  
Dynamic Responses ◽  
Deep Basin ◽  
Pipe Length ◽  
Axial Stability ◽  
Internal Water

A model test campaign of a large diameter water intake riser (WIR) has been planned, designed, and successfully executed in an offshore model basin. The objective of the model test is to better understand the global dynamic behavior of WIR, and thus advance its design. The scopes of the model test are to measure the response of the riser under floater motions; investigate the effect of the internal water and flow rate; and observe any vortex-induced-vibration (VIV) and axial instability due to motion and / or internal flow. The paper presents the model test results and the numerical calibrations and validations. The WIR pipe was carefully scaled and designed to meet the test objectives. The WIR in model test scale is 150 mm in inside diameter and approximately 36 m in length. The model test setup includes a fully instrumented riser, a planar motion mechanism (PMM) which simulates the vessel motion and an internal water flow system (IWFS). The riser was instrumented with Fiber Bragg Grating (FBG) strain sensors along the pipe length and circumference. The WIR was hung-off from the PMM inside the deep basin pit. More than 200 cases were carried out in the basin including the sinusoidal motion tests and random motion tests with different flow rates. The model tests collected a wealth of data of the WIR dynamic responses under the vessel motions and the internal water flow conditions. As expected, WIR global bending responses are highly dependent on the pipe excitation modes and their corresponding mode curvatures. These responses can be predicted well by numerical software through a calibration process. The axial response of WIR due to motion and/or internal flow is much more complex. The amount of internal water coupled with the pipe depends on the vessel motions and internal flow fluctuation. This is important for axial stability prediction and seawater lift system design.

Experimental Investigation on Vortex-Induced Vibration of a Free-Hanging Riser Under Vessel Motion

2016 ◽  
Author(s):  
Jungao Wang ◽  
Shixiao Fu ◽  
Muk Chen Ong ◽  
Huajun Li
Keyword(s):  
Prediction Models ◽  
Ocean Basin ◽  
Dynamic Responses ◽  
Test Cases ◽  
Response Frequency ◽  
Vortex Induced Vibration ◽  
Motion Trajectories ◽  
Out Of Plane ◽  
Future Prediction ◽  
Vessel Motion

A model test of a free-hanging riser under vessel motion was performed in the ocean basin at Shanghai Jiao Tong University to confirm whether vortex-induced vibration (VIV) can happen due to pure vessel motion, to investigate the equivalent current velocity and Keulegan–Carpenter (KC) number effect on the VIV responses and to obtain the correlations for free-hanging riser VIV under vessel motion with VIV for other compliant risers. Top end of the riser was forced to oscillate at given vessel motion trajectories. Fiber Brag Grating (FBG) strain sensors were used to measure the riser dynamic responses. Experimental results confirmed that the free-hanging riser would experience significant out-of-plane VIV. Meanwhile, VIV responses in terms of response amplitude, response frequency and cross-section trajectories under different test cases were further compared and discussed. Most importantly, the correlation among VIV response frequency, vortex shedding pairs and maximum KC number KCmax was revealed. The presented work is supposed to provide useful references for gaining a better understanding on VIV induced by vessel motion, and for the development of future prediction models.

Experimental Investigation on Vortex-Induced Vibration of a Free-Hanging Riser Under Vessel Motion and Uniform Current

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Jungao Wang ◽  
Shixiao Fu ◽  
Jiasong Wang ◽  
Huajun Li ◽  
Muk Chen Ong
Keyword(s):  
Prediction Models ◽  
Ocean Basin ◽  
Dynamic Responses ◽  
Ocean Current ◽  
Response Frequency ◽  
Vortex Induced Vibration ◽  
Out Of Plane ◽  
Future Prediction ◽  
Uniform Current ◽  
Vessel Motion

A model test of a free-hanging riser under vessel motion and uniform current is performed in the ocean basin at Shanghai Jiao Tong University to address four topics: (1) confirm whether vortex-induced vibration (VIV) can happen due to pure vessel motion; (2) to investigate the equivalent current velocity and Keulegan–Carpenter (KC) number effect on the VIV responses; (3) to obtain the correlations for free-hanging riser VIV under vessel motion with VIV for other compliant risers; and (4) to study the similarities and differences with VIV under uniform current. The top end of the riser is forced to oscillate or move, in order to simulate vessel motion or ocean current effects. Fiber Bragg Grating (FBG) strain sensors are used to measure the riser dynamic responses. Experimental results confirm that the free-hanging riser will experience significant out-of-plane VIV under vessel motion. Meanwhile, vessel motion-induced VIV responses in terms of response amplitude, response frequency, and cross section trajectories under different test cases are further discussed and compared to those under ocean uniform current. Most importantly, the correlation among VIV response frequency, vortex shedding pairs, and maximum KC number KCmax is revealed. The presented work is supposed to provide useful references for gaining a better understanding on VIV of a free-hanging riser and for the development of future prediction models.

Experimental investigation on vortex-induced force of a Steel Catenary Riser under in-plane vessel motion

2021 ◽  
Vol 78 ◽  
pp. 102882
Author(s):  
Mengmeng Zhang ◽  
Shixiao Fu ◽  
Chang Liu ◽  
Haojie Ren ◽  
Yuwang Xu
Keyword(s):  
Experimental Investigation ◽  
Steel Catenary Riser ◽  
Vessel Motion

Coupled Analysis of SCR and Flowline Under High Pressure and High Temperature

2014 ◽  
Author(s):  
C. H. Luk ◽  
Xinhai Qi ◽  
Jianxia Zhong
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Thermal Stresses ◽  
Dynamic Responses ◽  
Coupled Analysis ◽  
Finite Element Program ◽  
Steel Catenary Riser ◽  
Element Program ◽  
Lateral Displacements ◽  
Vessel Motion

This paper presents a coupled design analysis for a Pipe-in-Pipe (PIP) Steel Catenary Riser (SCR) and Flowline (FL) system in 5000ft of water under high pressure and high temperature (HP/HT) conditions in the Gulf of Mexico (GOM). The finite element program ABAQUS is used to model the inner and outer pipes of the PIP system, the centralizer, the SCR hangoff, the flowline lateral and end supports, and pipe-soil interactions on the seabed. Thermal stresses and stress ranges caused by repeated temperature transients, axial and lateral displacements of SCR and flowline, as well as by the dynamic responses of the coupled riser and flowline system, are presented. Comparisons are also made with results by ABAQUS models with beam and pipe elements, and results obtained by coupled and de-coupled analysis. The sample vessel motion was obtained for an example Spar platform in GOM.

Experimental Study of Hydrodynamic Damping for Water Intake Risers

2020 ◽  
Author(s):  
Zhenguo Gao ◽  
Mike Efthymiou ◽  
Wenhua Zhao ◽  
Liang Cheng ◽  
Tongming Zhou
Keyword(s):  
Fatigue Life ◽  
Natural Gas ◽  
Water Intake ◽  
Relative Velocity ◽  
Cooling Water ◽  
Small Motion ◽  
Hydrodynamic Damping ◽  
Steady Current ◽  
Helical Strakes ◽  
Vessel Motion

Abstract Water Intake Riser (WIR), conveying cooling water from the sea, is key to liquefaction of natural gas in the Floating Liquefied Natural Gas (FLNG) facility. Due to the wave-induced vessel motion, WIRs may experience resonant vibrations, which influence its fatigue life. In such situations, the estimate of hydrodynamic damping is critical to the prediction of fatigue life. Due to its small motion amplitudes compared to the diameter of WIR, the Keulegan–Carpenter (KC) for motion-induced flow around WIR is normally small (e.g. KC < 5). For small KC values, the effect of steady current on the hydrodynamic damping is not well understood and the current practice of using the relative velocity Morison model for predicting the hydrodynamic damping with in-line steady current is challenged by guidelines such as DNVGL-RP-C205 and ISO-19902. In this study, the hydrodynamic damping of a smooth WIR oscillating in still water or in steady currents is measured with a series of experiments at KC < 5 and the Reynolds number (Re) in the range of 103 ∼ 105. The effect of in-line or cross steady currents on the in-line hydrodynamic damping is investigated and the performance of the relative velocity Morison model for predicting the hydrodynamic damping at low KC is examined. Experiments are also conducted for a WIR with helical strakes in in-line or cross currents. Based on these experimental results, recommendations are made for predicting hydrodynamic damping in the WIR design.

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