Three-Dimensional Simulations of Offshore Oil Platform in Square and Diamond Arrangements

The interaction of the solitary wave with an oil platform composed of four vertical circular cylinders is investigated for two attack angle of the solitary wave β = 0 ° (square arrangement) and β = 45 ° (diamond arrangement). The solitary wave is generated using an internal source line as proposed by Hafsia et al. (2009). This generation method is extended to three-dimensional wave flow and is integrated into the PHOENICS code. The volume of fluid approach is used to capture the free surface evolution. The present model is validated in the case of a solitary wave propagating on a flat bottom for H / h = 0.25 where H is the wave height and h is the water depth. Compared to the analytical solution, the pseudowavelength and the wave crest are well reproduced. For a solitary wave interacting with square and diamond cylinders, the simulated results show that the maximum run-ups are well reproduced. For the diamond arrangements, the diffraction process seems to not affect the maximum run-ups, which approached the isolated cylinder. For the square arrangement, the shielding effect leads to a maximum wave force more pronounced for the upstream cylinder array.

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Solitary Wave Diffraction with a Single and Two Vertical Circular Cylinders

Mathematical Problems in Engineering ◽

10.1155/2021/6634762 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Zouhair Hafsia ◽

Saliha Nouri ◽

Salah Mahmoud Boulaaras ◽

Ali Allahem ◽

Salem Alkhalaf ◽

...

Keyword(s):

Solitary Wave ◽

Wave Diffraction ◽

Present Model ◽

Three Dimensional ◽

Wave Generation ◽

Transport Equations ◽

Circular Cylinders ◽

Wave Crest ◽

Wave Flow ◽

Wave Forces

This study investigates the three-dimensional (3-D) solitary wave interaction with two cylinders in tandem and side-by-side arrangements for two wave heights. The solitary wave generation and propagation are predicted using the volume of fluid method (VOF) coupled with the NavierStokes transport equations. The PHOENICS code is used to solve these transport equations. The solitary wave generation based on the source line developed by Hafsia et al. (2009) is extended in three-dimensional wave flow and is firstly validated for solitary waves propagating on a flat bottom. The comparison between numerical results and analytical solution for small wave height H / h = 0.1 and 0.2 shows good agreements. The wave crest and the pseudo-wavelength are well reproduced. Excellent agreements were found in terms of maximum run-up and wave forces by comparison with the present model and analytical studies. The present model can be tested for the extreme solitary wave to extend its application to a more realistic case study as the solitary wave diffraction with an offshore oil platform.

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Secondary and tertiary excitation of three-dimensional patterns on a falling film

Journal of Fluid Mechanics ◽

10.1017/s002211209400426x ◽

1994 ◽

Vol 270 ◽

pp. 251-276 ◽

Cited By ~ 20

Author(s):

H.-C. Chang ◽

M. Cheng ◽

E. A. Demekhin ◽

D. I. Kopelevich

Keyword(s):

Solitary Wave ◽

Three Dimensional ◽

Wave Structure ◽

Stationary Wave ◽

Wave Crest ◽

Checkerboard Pattern ◽

Secondary Transition ◽

Falling Film ◽

Two Dimensional ◽

Primary Instability

The primary instability of a falling film selectively amplifies two-dimensional noise down-stream over three-dimensional modes with transverse variation. If the initial three-dimensional noise is weak or if it has short wavelengths such that they are effectively damped by the capillary mechanism of the primary instability, our earlier study (Chang et al. 1993a) showed that the primary instability leads to a weakly nonlinear, nearly sinusoidal γ1 stationary wave which then undergoes a secondary transition to a strongly nonlinear γ2 wave with a solitary wave structure. We show here that the primary transition remains in the presence of significant three-dimensional noise but the secondary transition can be replaced by a selective excitation of oblique triad waves which can even include stable primary disturbances. The resulting secondary checkerboard pattern is associated with a subharmonic mode in the streamwise direction. If the initial transverse noise level is low, a secondary transition to a two-dimensional γ2 solitary wave is followed by a tertiary ‘phase instability’ dominated by transverse wave crest modulations.

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Interaction of a Solitary Wave with Vertical Fully/Partially Submerged Circular Cylinders with/without a Hollow Zone

Journal of Marine Science and Engineering ◽

10.3390/jmse8121022 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1022

Author(s):

Chih-Hua Chang

Keyword(s):

Circular Cylinder ◽

Solitary Wave ◽

Three Dimensional ◽

Vertical Cylinder ◽

Wave Model ◽

Circular Cylinders ◽

Cylinder Surface ◽

Wave Elevation ◽

Curvilinear Grid ◽

Nonlinear Potential

In this article, a three-dimensional, fully nonlinear potential wave model is applied based on a curvilinear grid system. This model calculates the wave action on a fully/partially submerged vertical cylinder with or without a hollow zone. As basic verification, a solitary wave hitting a single fully or partially submerged circular cylinder is tested, and our numerical results agree with the experimental results obtained by others. The influence of cylinder immersion depth and size on the wave elevation change on the cylinder surface is considered. The model is also applied to investigate the wave energy of a solitary wave passing through a hollow circular cylinder to determine the effect of the size and draft on the wave oscillating in the hollow zone.

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Wave Force on a Partially Submerged Fixed Horizontal Circular Cylinder

Volume 7A: Ocean Engineering ◽

10.1115/omae2018-77939 ◽

2018 ◽

Author(s):

Monica C. Silva ◽

Marcelo A. Vitola ◽

Paulo de Tarso T. Esperança ◽

Sergio H. Sphaier

Keyword(s):

Experimental Data ◽

Free Surface ◽

Circular Cylinder ◽

Wave Force ◽

Offshore Wind ◽

Circular Cylinders ◽

Wave Flow ◽

Energy Devices ◽

Floating Offshore Wind Turbines ◽

Horizontal Circular Cylinder

Circular cylinders are one of the most common geometries used in many structures, such as fixed platforms, risers, umbilical cables, offshore fish farms, floating offshore wind turbines, wave energy devices, plastic cleanup booms, and oil containment booms. Although partially submerged horizontal circular cylinders can be found in many offshore and marine structures, few works have investigated the influence of their positions beneath the free surface and the resulting wave force. The present work aimed to numerically study the wave force acting on a fixed horizontal circular cylinder near the free surface for different depths. The wave flow was modeled using a viscous model available in the StarCCM+ software using a two-dimensional numerical wave tank. The governing equations were solved using the finite volume in an unstructured mesh. A circular cylinder with a diameter (D) of 0.10 m and a regular wave with a steepness (H/L) of 0.025 were used in the present study. In this case, the cylinder diameter is much smaller than the wave length. Three different submerged depths were investigated, and the numerical results were compared with experimental data extracted from Dixon [1]. Good agreement was found for the first two cylinder positions (zc/D = 0 and −0.3). For the last case (zc/D = −0.5), a phase shift was observed. However, by correcting it, the agreement between the numerical and experimental data was also good.

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Surface Evolution and Wave Loads on a Horizontal Plate in Different Tsunami-like Waves

Journal of Earthquake and Tsunami ◽

10.1142/s1793431120400011 ◽

2020 ◽

Vol 14 (05) ◽

pp. 2040001

Author(s):

Qian Wang ◽

Yong-Liu Fang ◽

Hua Liu

Keyword(s):

Solitary Wave ◽

Wave Force ◽

Hydrodynamic Characteristics ◽

Vertical Force ◽

Wave Loads ◽

Horizontal Plate ◽

Local Pressure ◽

Surface Evolution ◽

Undular Bore ◽

Physical Experiments

Physical experiments are conducted to study the interaction between the tsunami-like waves and the horizontal plate. The surface evolution and wave-induced loads are measured to explore the hydrodynamic characteristics when different waves are employed to simulate the tsunami. The solitary wave, surge wave, and undular bore are generated in laboratory as the simplification of the offshore tsunami wave. The bottom-fixed plate places near the free surface. It is found that the elevated plate attenuates the solitary waves locally, while the submerged plate leads to the wave focus phenomenon. The plate has less influence on the surface variation of the surge wave propagating. Results of loads show the different loading process of each tsunami-like wave. The inertial wave force and the local pressure from the rising surface dominate the inline force and vertical force, respectively. The value of loads induced by the surge wave is less than that of the solitary wave. The undular bore is generated by the superimposition of the solitary wave on the surge wave. The part of the solitary wave plays a local role in the wave force, while the surge part dominates the surface evolution.

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Solitary-wave loads on a three-dimensional submerged horizontal plate: Numerical computations and comparison with experiments

Physics of Fluids ◽

10.1063/5.0043912 ◽

2021 ◽

Vol 33 (3) ◽

pp. 037129

Author(s):

Tian Geng ◽

Hua Liu ◽

Frederic Dias

Keyword(s):

Solitary Wave ◽

Three Dimensional ◽

Wave Loads ◽

Horizontal Plate ◽

Numerical Computations ◽

Submerged Horizontal Plate ◽

Comparison With Experiments

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Optical properties of three-dimensional woodpile photonic crystals composed of circular cylinders with planar defect structures

Applied Optics ◽

10.1364/ao.50.006657 ◽

2011 ◽

Vol 50 (36) ◽

pp. 6657

Author(s):

Shih-Hsuan Chung ◽

Jaw-Yen Yang

Keyword(s):

Optical Properties ◽

Photonic Crystals ◽

Three Dimensional ◽

Planar Defect ◽

Circular Cylinders ◽

Defect Structures

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Assessment of Numerical Methods for Plunging Breaking Wave Predictions

Journal of Marine Science and Engineering ◽

10.3390/jmse9030264 ◽

2021 ◽

Vol 9 (3) ◽

pp. 264

Author(s):

Shanti Bhushan ◽

Oumnia El Fajri ◽

Graham Hubbard ◽

Bradley Chambers ◽

Christopher Kees

Keyword(s):

Solitary Wave ◽

Wave Breaking ◽

Large Scale ◽

Turbulence Models ◽

Navier Stokes ◽

Wave Crest ◽

Breaking Wave ◽

Rans Turbulence Models ◽

Run Up ◽

Better Than

This study evaluates the capability of Navier–Stokes solvers in predicting forward and backward plunging breaking, including assessment of the effect of grid resolution, turbulence model, and VoF, CLSVoF interface models on predictions. For this purpose, 2D simulations are performed for four test cases: dam break, solitary wave run up on a slope, flow over a submerged bump, and solitary wave over a submerged rectangular obstacle. Plunging wave breaking involves high wave crest, plunger formation, and splash up, followed by second plunger, and chaotic water motions. Coarser grids reasonably predict the wave breaking features, but finer grids are required for accurate prediction of the splash up events. However, instabilities are triggered at the air–water interface (primarily for the air flow) on very fine grids, which induces surface peel-off or kinks and roll-up of the plunger tips. Reynolds averaged Navier–Stokes (RANS) turbulence models result in high eddy-viscosity in the air–water region which decays the fluid momentum and adversely affects the predictions. Both VoF and CLSVoF methods predict the large-scale plunging breaking characteristics well; however, they vary in the prediction of the finer details. The CLSVoF solver predicts the splash-up event and secondary plunger better than the VoF solver; however, the latter predicts the plunger shape better than the former for the solitary wave run-up on a slope case.

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