A numerical study of the load on cylindrical piles exerted by internal solitary waves

Oceanic observations from western Europe and the south-western Indian ocean have provided evidence of the generation of internal solitary waves due to an internal tidal beam impinging on the pycnocline from below – a process referred to as ‘local generation’ (as opposed to the more direct generation over topography). Here we present the first direct numerical simulations of such a generation process with a fully nonlinear non-hydrostatic model for an idealised configuration. We show that, depending on the parameters, different modes can be excited and we provide examples of internal solitary waves as first, second and third modes, trapped in the pycnocline. A criterion for the selection of a particular mode is put forward, in terms of phase speeds. In addition, another simpler geometrical criterion is presented to explain the selection of modes in a more intuitive way. Finally, results are discussed and compared with the configuration of the Bay of Biscay.

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A numerical study of the generation and propagation of internal solitary waves in the Luzon Strait

Oceanologica Acta ◽

10.1016/s0399-1784(02)01181-7 ◽

2002 ◽

Vol 25 (2) ◽

pp. 51-60 ◽

Cited By ~ 44

Author(s):

Shuqun Cai ◽

Xiaomin Long ◽

Zijun Gan

Keyword(s):

Solitary Waves ◽

Numerical Study ◽

Luzon Strait ◽

Internal Solitary Waves

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NONLINEAR OBLIQUE INTERACTION OF LARGE AMPLITUDE INTERNAL SOLITARY WAVES

Coastal Engineering Proceedings ◽

10.9753/icce.v33.waves.19 ◽

2012 ◽

Vol 1 (33) ◽

pp. 19

Author(s):

Keisuke Nakayama ◽

Taro Kakinuma ◽

Hidekazu Tsuji ◽

Masayuki Oikawa

Keyword(s):

Solitary Waves ◽

Water Waves ◽

Large Amplitude ◽

Numerical Study ◽

Incident Angle ◽

Resonant Interaction ◽

Internal Solitary Waves ◽

Weakly Nonlinear ◽

Wave Angle ◽

The One

Solitary waves are typical nonlinear long waves in the ocean. The two-dimensional interaction of solitary waves has been shown to be essentially different from the one-dimensional case and can be related to generation of large amplitude waves (including ‘freak waves’). Concerning surface-water waves, Miles (1977) theoretically analyzed interaction of three solitary waves, which is called “resonant interaction” because of the relation among parameters of each wave. Weakly-nonlinear numerical study (Funakoshi, 1980) and fully-nonlinear one (Tanaka, 1993) both clarified the formation of large amplitude wave due to the interaction (“stem” wave) at the wall and its dependency of incident angle. For the case of internal waves, analyses using weakly nonlinear model equation (ex. Tsuji and Oikawa, 2006) suggest also qualitatively similar result. Therefore, the aim of this study is to investigate the strongly nonlinear interaction of internal solitary waves; especially whether the resonant behavior is found or not. As a result, it is found that the amplified internal wave amplitude becomes about three times as much as the original amplitude. In contrast, a "stem" was not found to occur when the incident wave angle was more than the critical angle, which has been demonstrated in the previous studies.

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An Iterative Updating Method for Dynamic Responses of a Floating Platform Under Action of Internal Solitary Waves

Volume 1: Offshore Technology; Offshore Geotechnics ◽

10.1115/omae2019-96553 ◽

2019 ◽

Author(s):

Wang Junrong ◽

Du Junfeng ◽

Zhang Min ◽

Chang Anteng

Keyword(s):

South China Sea ◽

Solitary Waves ◽

South China ◽

Numerical Study ◽

Ocean Current ◽

Internal Solitary Waves ◽

Floating Structures ◽

Oil Companies ◽

China Sea ◽

Fluid Body

Abstract The internal solitary waves, have properties of two-way shear profile, significant velocity and acceleration, etc., which threaten the safety of deepwater floating systems in South China Sea (SCS), for the frequent occurrence and the high intensity of internal solitary waves in SCS. In recent years, offshore oil companies of China encountered many strong internal waves during its deepwater oil and gas exploration and development activities in South China Sea. However, the action mechanism of ISWs to floating structures is not understood clearly, and the internal solitary waves are classified as ocean current in API RP 2SK (3rd edition), therefore engineers ignore the velocity variance and long period “wave” characteristics in the design of floating structures. Furthermore, the offshore floating structures is oscillating under the action of environmental forces, due to the horizontal velocity of the platform is comparative to that of ISWs, thus fluid-body coupling is significant that one cannot analyse it by simply adding a specified ISW force time history to the floater. This paper proposes a new iterative updating method for ISW loading calculation considering the fluid-body coupling, and applied this method to a semi MODU, numerical study shows the iteration is efficient and the result is more reasonable compared to conventional method, and it is found that the maximal offset decreases significantly.

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A numerical study of rotation effect on the propagation of nonlinear internal solitary waves in the northern South China Sea

Applied Mathematical Modelling ◽

10.1016/j.apm.2017.01.085 ◽

2017 ◽

Vol 46 ◽

pp. 581-590 ◽

Cited By ~ 2

Author(s):

Xiaodong Deng ◽

Shuqun Cai

Keyword(s):

South China Sea ◽

Solitary Waves ◽

South China ◽

Numerical Study ◽

Northern South China Sea ◽

Internal Solitary Waves ◽

Rotation Effect ◽

China Sea

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A Numerical Study of the Forces on Two Tandem Cylinders Exerted by Internal Solitary Waves

Mathematical Problems in Engineering ◽

10.1155/2016/9086246 ◽

2016 ◽

Vol 2016 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Yin Wang ◽

Lingling Wang ◽

Hai Zhu ◽

Hongwu Tang ◽

Gang Wei

Keyword(s):

Solitary Waves ◽

Numerical Study ◽

Three Dimensional ◽

Circular Cylinders ◽

Internal Solitary Waves ◽

Gradient Distribution ◽

Numerical Wave Flume ◽

Wave Flume ◽

Eddy Simulation ◽

Les Model

A three-dimensional numerical wave flume is employed to investigate the forces exerted by internal solitary waves (ISWs) on a pair of circular cylinders in tandem arrangement, using large-eddy simulation (LES) model. The effect of the centre-to-centre distance (L) ranging from 1.5 to 5 diameters (D) is studied for various ISWs amplitudes (ηa) in the two-layer fluid system. Vertical-averaged vorticity distribution and vertical-averaged pressure gradient distribution in each layer are presented to investigate the different hydrodynamic interference between cylinders and the ISWs forces on each cylinder at variousL. Furthermore, the force behaviors of the two cylinders are also compared with that of an isolated cylinder in the same environment. The interaction between the two piles occurs in both layers, and it is found that, for1.5≤L/D<3.5, strong mutual interference appears between two cylinders; for3.5≤L/D<5, the two cylinders continue to influence each other in a weak-interference state; forL/D≥5, the interaction gradually decreases into a noninteracting state. This paper tries to provide some references to structural arrangement of double-cylinder structure and grouped-cylinder structure in stratified flow environment.

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