Dynamic performance of a long curved river-crossing pipeline system with multiple floating bodies during immersion process

2021 ◽  
Vol 234 ◽  
pp. 109204
Author(s):  
Zhiwen Wu ◽  
Yangyang Xiao ◽  
Huihuan Ma ◽  
Pengpeng Ni ◽  
PingJun Lin ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Pipeline System ◽  
Floating Bodies ◽  
Multiple Floating Bodies

Reduced-Order Time-Domain Simulation of Floating Bodies for Efficient Design Analysis

2015 ◽  
Author(s):  
Hyun Y. Kim ◽  
Stephanie L. Fitzpatrick ◽  
David C. Kring
Keyword(s):  
Memory Function ◽  
Computational Effort ◽  
Impulse Response Functions ◽  
Time Domain Simulation ◽  
Efficient Design ◽  
Floating Bodies ◽  
Order Model ◽  
Reduced Order ◽  
Multi Body ◽  
Multiple Floating Bodies

This paper describes the development and implementation of a reduced-order model to represent the hydrodynamic forces acting on a ship using Impulse-Response Functions (IRF). The approach will be conducted using Aegir, a timedomain seakeeping program that uses an advanced, Non-Rational Uniform B-Spline (NURBS) based, high-order boundary element method. The Cummins equation is slightly modified such that the memory function is decomposed into two terms: one for the impulsive velocity and the other term for the impulsive displacement. The present approach also further develops a method to simulate interactions between multiple floating bodies. The IRF convolutions for the free surface memory effect significantly reduce the computational effort compared to direct simulation. This will be demonstrated for both single and multi-body forward-speed, seakeeping simulations.

Wave forces on multiple floating bodies

1982 ◽  
Vol 4 (1) ◽  
pp. 2-8 ◽  
Author(s):  
Akira Masumoto ◽  
Yoshio Yamagami ◽  
Ryuji Sakata
Keyword(s):  
Wave Forces ◽  
Floating Bodies ◽  
Multiple Floating Bodies

Wave Drift Forces' Calculation on Two Floating Bodies Based on the Boundary Element Method—Attempt for Improvement of the Constant Panel Method

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Qiao Li ◽  
Yasunori Nihei
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Evaluation Method ◽  
Panel Method ◽  
Floating Bodies ◽  
Wave Drift ◽  
Wave Drift Forces ◽  
Multiple Floating Bodies ◽  
Drift Forces ◽  
Element Method

An improved constant panel method for more accurate evaluation of wave drift forces and moment is proposed. The boundary element method (BEM) of solving boundary integral equations is used to calculate velocity potentials of floating bodies. The equations are discretized by either the higher-order boundary element method or the constant panel method. Though calculating the velocity potential via the constant panel method is simple, the results are unable to accurately evaluate wave drift forces and moment. An improved constant panel method is introduced to address these issues. The improved constant panel method can, without difficulty, employ the near-field method to evaluate wave drift forces and moment, especially for multiple floating bodies. Results of the new evaluation method will be compared with other evaluation method. Additionally, hydrodynamic interaction between multiple floating bodies will be assessed.

Simulation and Experiment on the Vibration Performance of Pre-Loaded Multi-Plies Bellows

2010 ◽  
Vol 455 ◽  
pp. 476-480 ◽  
Author(s):  
Wei Ma ◽  
Yong Jian Yu ◽  
Yong Gang Liu ◽  
Ji Shun Li ◽  
Yu Jun Xue
Keyword(s):  
Finite Element Method ◽  
Dynamic Performance ◽  
Sound Insulation ◽  
Pipeline System ◽  
Hydraulic Pressure ◽  
Flexible Joint ◽  
Simulation And Experiment ◽  
Major Equipment ◽  
Stiffness And Damping ◽  
Vibration Performance

As major equipment for damping and sound insulation, bellows are used as flexible joint and elastic element in the pipeline system of naval ships. In this paper, Finite Element Method was adopted to analyze the static and dynamic performance of bellows. Fourply bellows model was built, which 0~1.2MPa pressure is loaded. Then the stress, vibrating type and frequency of bellows were gotten. The result of simulation shows that the frequency of bellows increases linearly with the increase of pre-loaded. New equipment was produced to test the vibration performance of bellows. The vibration performance of fourply bellows was researched. The frequency, stiffness and damping of bellows were gotten. Some rules were summarized. The result of experiment shows that the frequency and stiffness of bellows increase with the increase of hydraulic pressure. In addition, while the hydraulic pressure is less than 0.8MPa, the damping of bellows increases with the increase of hydraulic pressure. While the hydraulic pressure is more than 0.8MPa, the damping decreases with the increase of hydraulic pressure.

Resonant Motion of Liquid Confined between Floating Structures

2014 ◽  
Vol 567 ◽  
pp. 289-294
Author(s):  
N.V. Nasma Noor ◽  
A.P. Shashikala
Keyword(s):  
Resonant Frequency ◽  
Frequency Domain Method ◽  
Diffraction Radiation ◽  
Floating Bodies ◽  
Floating Structures ◽  
Hydrodynamic Behaviour ◽  
Wave Elevation ◽  
Close Proximity ◽  
Multiple Floating Bodies ◽  
Two Bodies

Many applications occur in the field of marine hydrodynamics where two or more vessels are in sufficiently close proximity to experience significant wave action. The motion of such floating bodies in waves is frequency dependent. In the case of multiple floating bodies, when resonance occurs, the effect of confined liquid between the bodies has some serious implications on the safety and operation of the offloading system. The main objective of the work is to determine the hydrodynamic behaviour of two bodies freely floating in water. A frequency domain method is adopted for the prediction of the resonant frequency. 3D linear diffraction radiation analysis is used to solve the problem. Structures are modelled in ANSYS AQWA and analysed in selected range of frequency with different spacing. As the spacing increases the resonant frequency in roll is found to be decreasing for both ship and tugboat and the frequency shift between the two is increasing. The wave elevation pattern within the spacing has been observed and the result has been shown for different spacings.

A Numerical Investigation on Hydrodynamics of Multiple Floating Bodies in Offshore Installation Engineering

2013 ◽  
Vol 477-478 ◽  
pp. 285-291
Author(s):  
Zuo Yong Zhang ◽  
Li Ping Sun
Keyword(s):  
Environmental Parameters ◽  
Linear Potential ◽  
Floating Bodies ◽  
Spar Platform ◽  
Scheme Design ◽  
Good Advice ◽  
Transport Ship ◽  
Marine Engineering ◽  
Linear Potential Theory ◽  
Multiple Floating Bodies

There are many applications in marine engineering where two or more floating vessels are in close proximity. Probably the most significant one is related to the offshore installation engineering. On the background of the upper module installation operation of spar platform, this paper investigates the hydrodynamic interaction effects of multiple floating bodies in offshore installation engineering. The numerical simulation bases on the 3-D frequency domain linear potential theory. The calculations are carried out for the crane ship, the transport ship and the spar platform. Finally the best environmental parameters and the relative position of floating bodies are selected, which can provide good advice on installation operation scheme design.

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