A 3-D numerical study of the random wave-induced response in a spatially heterogenous seabed

2021 ◽  
Vol 135 ◽  
pp. 104159
Author(s):  
Bin Zhu ◽  
Tetsuya Hiraishi ◽  
Hajime Mase ◽  
Yasuyuki Baba ◽  
Huafu Pei ◽  
...  
1996 ◽  
Vol 23 (2) ◽  
pp. 340-346
Author(s):  
Michael Isaacson ◽  
John Baldwin ◽  
Andrew Kennedy

This paper describes an experimental and a numerical study of the wave-induced response of a moored vessel near a reflecting wall, for the purpose of incorporating wave reflection effects into wave agitation criteria for small craft harbours. The motions of a model vessel have been measured for a range of wave heights, wave periods, wave directions, mooring conditions, and vessel locations, and with both regular and irregular waves. These have been compared with the results of a numerical model based on linear diffraction theory. An expression is developed to relate vessel motions near a partially reflecting wall to motions in unreflected waves. This has been found to agree well with the experimental results, and is used to recommend an extension to existing wave agitation criteria for small craft harbours so as to take account of the presence of reflecting walls. Key words: coastal engineering, harbours, hydrodynamics, marinas, wave agitation, waves.


2021 ◽  
Vol 930 ◽  
Author(s):  
I.A. Milne ◽  
O. Kimmoun ◽  
J.M.R. Graham ◽  
B. Molin

The wave-induced resonant flow in a narrow gap between a stationary hull and a vertical wall is studied experimentally and numerically. Vortex shedding from the sharp bilge edge of the hull gives rise to a quadratically damped free surface response in the gap, where the damping coefficient is approximately independent of wave steepness and frequency. Particle image velocimetry and direct numerical simulations were used to characterise the shedding dynamics and explore the influence of discretisation in the measurements and computations. Secondary separation was identified as a particular feature which occurred at the hull bilge in these gap flows. This can result in the generation of a system with multiple vortical regions and asymmetries between the inflow and outflow. The shedding dynamics was found to exhibit a high degree of invariance to the amplitude in the gap and the spanwise position of the barge. The new measurements and the evaluation of numerical models of varying fidelity can assist in informing offshore operations such as the side by side offloading from floating liquefied natural gas facilities.


Author(s):  
Andrew H. C. Chan ◽  
Jian-Hua Ou

Wave-induced liquefaction is one of the main factors influence the stability of marine structures. However, the investigation on this phenomenon is complicated as the dynamic interaction between soil, pore fluid and the structure is closely coupled. In order to obtain a better understanding of the wave-induced response around the circular caisson founded in the seabed, three dimensional numerical analyses have been performed using the 3D finite element program DYNE3WAC in order to investigate the wave-induced response around the circular caisson.


2018 ◽  
Vol 1 (4) ◽  
pp. 1-11 ◽  
Author(s):  
Mohammad Mohammad Beigi Kasvaei ◽  
◽  
Mohammad Hossein Kazeminezhad ◽  
Abbas Yeganeh-Bakhtiary ◽  
◽  
...  

2018 ◽  
Vol 157 ◽  
pp. 364-375 ◽  
Author(s):  
Chencong Liao ◽  
Dagui Tong ◽  
Dong-Sheng Jeng ◽  
Hongyi Zhao

1999 ◽  
Vol 43 (04) ◽  
pp. 229-240
Author(s):  
H. R. Riggs ◽  
R. C. Ertekin

One design for a mobile offshore base is to link serially as many as five large semisubmersibles to form a platform long enough to support large aircraft. This paper investigates the linear, wave-induced response characteristics of serially-connected semisubmersibles. A major motivation of this study is to understand more completely the forces required to link semisubmersible modules. The impact of connector strategy and damping on the response, especially the connector forces, is investigated, and the response "modes" which contribute to the connector forces are evaluated in detail. It is shown that the response characteristics can be impacted significantly by the connection strategy, and that connector damping can be a significant source of energy loss when compared to radiation damping. The wet natural frequencies and normal modes are also determined and used to explain the response characteristics of different connection strategies. Although the analyses are based on a specific semisubmersible design, the results provide insight on how other systems of connected semisubmersibles would likely behave.


2021 ◽  
Vol 240 ◽  
pp. 109869
Author(s):  
Bei Chu ◽  
Yiren Chen ◽  
Yao Zhang ◽  
Guangming Zhang ◽  
Xu Xiang ◽  
...  

2019 ◽  
Vol 1 (11) ◽  
Author(s):  
Richard Asumadu ◽  
Jisheng Zhang ◽  
H. Y. Zhao ◽  
Hubert Osei-Wusuansa ◽  
Alex Baffour Akoto

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2121 ◽  
Author(s):  
Hasan Al-Rifaie ◽  
Wojciech Sumelka

Blast resistant gates/doors are essential for sensitive infrastructure, such as embassies, ministries, or parliaments. Lightweight gates equipped with ‘energy absorbing systems’ have better operational performance than the traditional costly and bulky design. Graded auxetic structures have not yet been used as potential passive damping systems in the supporting frame of blast resistant gates. Consequently, this study tries to test if a uniaxial graded auxetic damper (UGAD) proposed by the authors in a recent article, namely the development of a new shock absorbing UGAD, could maintain a 3000 mm × 4500 mm steel gate operable after high blast peak reflected overpressure of 6.6 MPa, from 100 kg TNT at 5 m stand-off distance. The blast-induced response of the gate was assessed, with and without the proposed UGAD, using Abaqus/Explicit solver. Results showed that the attachment of the proposed UGAD to the gate led to a dramatic decrease in permanent deformations (a critical factor for gate operability after a blast event). Hence, a lighter, more economical gate (with 50% reduction in mass) was required to satisfy the operability condition. In addition, 49% of peak reaction forces were diminished, that have a direct impact on the supporting frame. Moreover, the results revealed that, in the numerical model, 56% of the achieved plastic dissipation energy was from the UGADs, and 44% from the gate. The outcomes of this research may have a positive impact on other sectors beyond academia, such as industry, economy, and public safety.


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