• Title/Summary/Keyword: 3차원 VOF법

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3-Dimensional Analysis for Nonlinear Wave Forces Acting on Dual Vertical Columns and Their Nonlinear Wave Transformations (복수 연직 주상구조물에 작용하는 비선형파력과 구조물에 의한 비선형파랑변형의 3차원해석)

  • Lee, Kwang-Ho;Lee, Sang-Ki;Shiin, Dong-Hoon;Kim, Do-Sam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.1
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    • pp.1-13
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    • 2008
  • In the present work, wave transformation by vertical columns and its wave forces acting on them are discussed using a direct 3-D numerical model based on the VOF (Volume Of Fluid) method. The numerical results for wave transformations and wave forces are critically compared to an advanced experimental data, and provide the verification of the numerical model used in the present study. Overall model-data comparisons are good. After verification of the numerical model, it is used to simulate wave fields around dual vertical columns with arbitrary cross section, and the characteristics of nonlinear wave forces and wave transformations according to the variations of different cross section types of vertical columns, an interval of vertical columns and incident wave angle are discussed.

Wave Forces Acting on Vertical Cylinder and Their Wave Transformations by 3-Dimensional VOF Method (3차원 VOF법에 의한 연직 주상구조물에 작용하는 파력과 구조물에 의한 파랑변형 해석)

  • Lee, Kwang-Ho;Lee, Sang-Ki;Sin, Dong-Hoon;Kim, Chang-Hoon;Kim, Do-Sam
    • Journal of Ocean Engineering and Technology
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    • v.21 no.2 s.75
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    • pp.12-21
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    • 2007
  • As the economy grows and the population increases, we need to develop our coastal area and make use of it for various purposes. Specifically, investigation of the wave interactions on and around the vertical cylinders is very important in the design of the offshore or coastal structures. The nonlinear potential analysis developed so far, although very useful, has been found to be limited in application, as strong nonlinear waves generated by the interference between multilayered cylinders and wave impact forces by breaking waves can hardly be estimated. In this study, using a 3-Dimensional volume tracking method VOF(Volume of Fluid), based on Namer-Stokes equations, was developed to simulate highly nonlinear effects, such as breaking waves at the interface or complicated interference waves among structures. A numerical method for nonlinear interaction wave and vertical cylinders is newly proposed. The wave forces and wave transformations computed by the newly proposed numerical simulation method were compared to the other researcher's experimental results, and the results agree well. Based on the validation of this study, this numerical method is applied to the two vertical cylinders to discuss their nonlinear wave forces and wave transformations, according to the variations of separate distance of vertical cylinders.

Analysis of Wave Forces Acting on Vertical Cylinder and Wave Transformations by S-Dimensional VOF Method (3차원 VOF법에 의한 주상구조물에 작용하는 파력과 파랑변형 해석)

  • Lee, Sang-Ki;Kim, Chang-Hoon;Kim, Do-Sam;Sin, Dong-Hoon
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.377-381
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    • 2006
  • Recently, as economy grow and population increase we need to develop our coastal area and make good use of it for various purposes. That's why large structures are being installed on the sea. Some samples are petroleum storage tanks, pier of sea bridges. These are large structures which have been installed at coastal area. When we design such vertical cylinder, we should avoid too much construction expense caused by excessive designing or by lack of sufficient design. In order to prevent excessive expenditure, it is important to correctly calculate the force of waves acting on structures and predict the wave transformation. In this study, apply to VOF method based on Navier-Stokes equation and then discussed that nonlinear wave force and wave transformation. A comparison between the numerical model and existing experimental results showed nice agreement among them.

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A Numerical Simulation of Wave Run-up Around Circular Cylinders in Waves (파랑중 원형 실린더 주위 Wave Run-up 시뮬레이션)

  • Cha, Kyung-Jung;Jung, Jae-Hwan;Seo, Kwang-Cheol;Koo, Bon-Guk
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.6
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    • pp.750-757
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    • 2016
  • This study presents the wave run-up height around single and multiple surface-piercing cylinders according to wave period and steepness. In order to simulate 3D incompressible viscous two-phase turbulent flow, the present study employed a volume of fluid (VOF) method with realizable $k-{\varepsilon}$ turbulence model based on commercial Computational Fluid Dynamics (CFD) software, "STAR-CCM". The wave periods at model scale were 1.269s and 1.692s for a single cylinder and 1.716s for multiple cylinders. In each case, wave steepness of has 1/30 and 1/16 were used, respectively. Consequently, the results for wave run-up height with regard to wave steepness and period were compared with those of relevant previous experimental studies. The numerical simulation results showed a good qualitative agreement with experiments.

A Study on Wave Responses of Vertical Tension-Leg Circular Floating Bodies (연직인장계류된 원형부유체의 파랑응답에 관한 연구)

  • Lee, Kwang-Ho;Kim, Chang-Hoon;Kim, Do-Sam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.3
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    • pp.248-257
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    • 2011
  • In the present study, we proposed a new numerical wave tank model to analyze the vertical tension-leg circular floating bodies, using a 2-D Navier-Stokes solver. An IBM(Immersed Boundary Method) capable of handling interactions between waves and moving structures with complex geometry on a standard regular Cartesian grid system is coupled to the VOF(Volume of Fluid) method for tracking the free surface. Present numerical results for the motions of the floating body were compared with existing experimental data as well as numerical results based on FAVOR(Fractional Area Volume Obstacle Representation) algorithm. For detailed examinations of the present model, the additional hydraulic experiments for floating motions and free surface transformations were conducted. Further, the versatility of the proposed numerical model was verified via the numerical and physical experiments for the general rectangular floating bodies. Numerical results were compared with experiments and good agreement was archived.

Numerical Simulation of Velocity Fields and Vertex Generation around the Submerged Breakwater on the Sloped Bottom (경사수역에 설치된 잠제 주변의 유속장과 와의 발생에 대한 수치모의)

  • 허동수;김도삼
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.15 no.3
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    • pp.151-158
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    • 2003
  • The study of velocity fields and vortex generation around the submerged breakwater can be utilized as materials related to understanding of wave dissipation mechanism, sediment transport, and stability of structure. In the present study, two-dimensional numerical wave flume, based on the VOF method to trace free surface, developed by Kim et al.(2001, 2002) was used to numerically simulate velocity fields and vortex generation around the impermeable submerged breakwater installed at the uniform bottom. Especially, the characteristics of vortex generation due to the geometry of the structure and incident wave conditions are examined through the analysis of averaged-velocity fields around the impermeable submerged breakwater. From the numerical simulations, it is confirmed that a counter clockwise vortex is formed in front of the structure and a clockwise vortex develops behind the structure. Also, incident wave height and period have an sensitive effect on the strength of vortex.

A Study of the Wave Control Characteristics of the Permeable Submerged Breakwater using VOF Method in Irregular Wave Fields (불규칙파동장에 있어서 VOF법에 의한 투과성잠제의 파랑제어 특성에 관한 연구)

  • Kim Do Sam;Lee Kwang Ho;Yoo Hyun Sang;Kim Chang Hoon;Son Byoung Kyu
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.16 no.3
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    • pp.121-129
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    • 2004
  • The different types of coastal souctures have been constructed for the protection of coastal region from the incident waves. Among them. the permeable submerged breakwater has been widely used as a wave dissipater and sediment transport controller because of its excellent advantages in scenery effects, construction efficiency and environment aspects. This study numerically investigated the characteristics of wave energy variations and transmission coefficient at the rear of the permeable submerged breakwater installed in the irregular wave field. To analyze it's performance numerically, a two-dimensional numerical wave flume based on VOF method was used. A frequency spectral analysis showed that the spectral peak moved to the short-period in the one-row submerged breakwater, and the wave energy was distributed evenly for the whole period in the two-row submerged breakwater in the case of breaking on the submerged breakwater. The spectral peak was shown to be converged within the significant wave period at the rear of the permeable submerged breakwater in the case of non-breaking conditions. From the result of transmission coefficients analysis. it was confirmed that a considerable quantity of wave energy was transmitted to the rear of the permeable submerged breakwater in the case of non-breaking rather than breaking.