Numerical simulation of free-surface waves past two semi-submerged horizontal circular cylinders in tandem

Ong, Muk Chen; Kamath, Arun; Bihs, Hans; Afzal, Mohammad Saud

doi:10.1016/j.marstruc.2016.11.002

Cited by 33 publications

(11 citation statements)

References 16 publications

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“…where p represents the pressure and τ is the normal component of the stress tensor. The numerical model has been used in the past for a wide range of marine applications such as wave-structure interaction [50,51], breaking wave forces [35], floating body dynamics [48], sloshing [52], irregular wave analysis [24,37,53] and sediment transport [54].…”

Section: Overview Of the Numerical Schemesmentioning

confidence: 99%

Free Surface Reconstruction for Phase Accurate Irregular Wave Generation

Aggarwal

Pákozdi

Bihs

et al. 2018

JMSE

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The experimental wave paddle signal is unknown to the numerical modellers in many cases. This makes it quite challenging to numerically reproduce the time history of free surface elevation for irregular waves. In the present work, a numerical investigation is performed using a computational fluid dynamics (CFD) based model to validate and investigate a non-iterative free surface reconstruction technique for irregular waves. In the current approach, the free surface is reconstructed by spectrally composing the irregular wave train as a summation of the harmonic components coupled with the Dirichlet inlet boundary condition. The verification is performed by comparing the numerically reconstructed free surface elevation with theoretical input waves. The applicability of the present approach to generate irregular waves by reconstructing the free surface is investigated for different coastal and marine engineering problems. A numerical analysis is performed to validate the free surface reconstruction approach to generate breaking irregular waves over a submerged bar. The wave amplitudes, wave frequencies and wave phases are modelled with good accuracy in the time-domain during the higher-order energy transfers and complex processes like wave shoaling, wave breaking and wave decomposition. The present approach to generate irregular waves is also employed to model steep irregular waves in deep water. The free surface reconstruction method is able to simulate the irregular free surface profiles in deep water with low root mean square errors and high correlation coefficients. Furthermore, the irregular wave forces on a monopile are investigated in the time-domain. The amplitudes and phases of the force signal under irregular waves generated by using the current technique are modelled accurately in the time-domain. The proposed approach to numerically reproduce the free surface elevation in the time-domain provides promising and accurate results for all the benchmark cases.

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Section: Overview Of the Numerical Schemesmentioning

confidence: 99%

Free Surface Reconstruction for Phase Accurate Irregular Wave Generation

Aggarwal

Pákozdi

Bihs

et al. 2018

JMSE

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“…The model is based on a finite-difference framework with a staggered structured numerical grid and obtains the free surface using the level set method. The model has been previously applied to study several complex-free surface phenomena such as focussed wave forces , hydrodynamics of semi-submerged cylinders (Ong et al 2017), water impact and entry , and floating bodies in waves . The wave interaction with an impervious submerged step is simulated and the wave kinematics are compared to data obtained from experiments carried out at NTNU Trondheim.…”

Section: Introductionmentioning

confidence: 99%

Modeling porous coastal structures using a level set method based VRANS-solver on staggered grids

Sasikumar

Kamath

Bihs

2020

Coastal Engineering Journal

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Several engineering problems in the field of coastal and offshore engineering involve flow interaction with porous structures such as breakwaters, sediment screens, and scour protection devices. In this paper, the interaction of waves with porous coastal structures using an opensource computational fluid dynamics (CFD) model is presented. The fluid flow through porous media is modeled using the Volume-averaged Reynolds-averaged Navier-Stokes (VRANS) equations. Novel improvements to the numerical grid architecture and discretization schemes are made, with a staggered numerical grid for better pressure-velocity coupling and higherorder schemes for convection and time discretization. New interpolation schemes required for the VRANS equations on a staggered grid are implemented. The flow problem is solved as a two-phase problem and the free surface is captured with the level set function. The model is validated by comparing the numerical results to experimental data for different cases such as flow through crushed rock, solitary, and regular wave interaction with a porous abutment and wave interaction with a breakwater considering the three different porous layers. The numerical results are also seen to be highly grid-independent according to the grid convergence study and show a significantly better agreement to experimental data in comparison to current literature.

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“…The results show that Reynolds number and Keulegan-Carpenter (KC) are two domination factors for the vibration of the submarine pipeline and the flow regime. Besides, Two-dimensional (2D) numerical simulations are performed to investigate free surface waves past two semi-submerged horizontal circular cylinders in tandem by Ong et al [10]. When free surface waves pass two semi-submerged horizontal cylinders in tandem, for the cases with small spacing between the two cylinders, more prominent wave run-up and over-topping actions and larger positive force on upstream cylinder are observed as compared with that of the single cylinder case.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves

Zhao

et al. 2019

Water

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Submarine pipelines have been extensively used for marine oil and gas extraction due to their high efficiency, safety, and low price. However, submarine pipelines are vulnerable to extreme waves (i.e., tsunami waves). Previous research has often used solitary waves as a basis for studying the impacts of tsunami waves on submarine pipelines, although the hydrodynamic characteristics and wave properties drastically differ from those of real-world tsunami waves. This paper numerically investigates the hydrodynamic characteristics of tsunami waves interacting with submarine pipelines, but instead uses an improved wave model to generate a tsunami-like wave that more closely resembles those encountered in the real-world. The tsunami-like wave generated based on a real-world tsunami wave profile recorded during a 2011 tsunami in Japan has been applied. Given the same wave height, simulation results show that peak hydrodynamic forces of the tsunami-like wave are greater than those of the solitary wave. Meanwhile, the duration of the acting force under the tsunami-like wave is much longer than that of the solitary wave. These findings underline the basic reasons for the destructive power of tsunamis. It is also noted that the hydrodynamic forces of the pipeline under the tsunami-like wave increase with wave height, but will decrease as water depth increases. In addition to the single pipeline, the complicated hydrodynamic characteristics of pipelines in tandem arrangement have been also numerically studied. It is believed that the findings drawn from this paper can enhance our understanding of the induced forces on submarine pipelines under extreme tsunami waves.

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Numerical simulation of free-surface waves past two semi-submerged horizontal circular cylinders in tandem

Cited by 33 publications

References 16 publications

Free Surface Reconstruction for Phase Accurate Irregular Wave Generation

Free Surface Reconstruction for Phase Accurate Irregular Wave Generation

Modeling porous coastal structures using a level set method based VRANS-solver on staggered grids

Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves

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