• Title/Summary/Keyword: Submerged breakwater

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Numerical Models of Water Wave with Parabolic and Hyperbolic Forms

  • Lee, Jong-Kyu;Lee, Chang-Hae
    • Korean Journal of Hydrosciences
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    • v.2
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    • pp.25-37
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    • 1991
  • The numerical models of the parabolic equation, applicable only to the progressive wave, and hyperblic equation, which may consider even the reflected wave, were developed and applied to the area of the submerged circular shoal and then results obtained from both models were compared with experimental measurements and each other. The hyperbolic model was further applied to both the detaced breakwater and the breakwater with a gap. The numerical results were plotted and compated with the existing data. Numerical solutions were obtained with the finite difference method.

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Development of Numerical Model for Scour Analysis under Wave Loads in Front of an Impermeable Submerged Breakwater (불투과 잠제 전면에서 파랑 작용 하의 세굴 해석을 위한 수치모델의 개발)

  • Hur, Dong-Soo;Jeon, Ho-Seong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.5B
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    • pp.483-489
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    • 2011
  • In this study, the coupled-numerical model has been newly developed to investigate numerically scouring and deposition around a coastal structure like a submerged breakwater using a numerical wave model and a lagrangian particle model for sand transport. As a numerical wave model, LES-WASS-2D (Hur and Choi, 2008) is adopted. The model is able to consider the flow through a porous midium with inertial, laminar and turbulent resistance term and determine the eddy viscosity with LES turbulence model. Distinct element method (Cundall and Strack, 1979), which is able to apply to many dynamical analysis of particulate media, as a lagrangian particle model for sand transport is newly coupled to the numerical wave model. The numerical simulation has been carried out to examine the scour problem in front of an impermeable submerged breakwater using the newly coupled-numerical model. The numerical results has been compared qualitatively with an existing experimental data and then its applicability has been discussed.

Effect of Multi-directional Random Waves on Characteristics of 3-D Wave Field around Permeable Submerged Breakwaters (다방향 불규칙파가 투과성 잠제 주변의 3차원 파동장에 미치는 영향)

  • Hur, Dong-Soo;Lee, Woo-Dong
    • Journal of Ocean Engineering and Technology
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    • v.26 no.2
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    • pp.68-78
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    • 2012
  • This study proposes an improved 3-D model that includes a new non-reflected wave generation system for oblique incident and multi-directional random waves, which enables us to estimate the effect of the various wave-types on 3-D wave fields in a coastal area with permeable submerged breakwaters. Then, using the numerical results,the three-dimensional wave field characteristics around permeable submerged breakwaters are examined in cases of oblique incident and multi-directional random waves. Especially, the wave height, mean surface elevation and mean flow around the submerged breakwaters are discussed in relation to the variation of incident wave condition.

Regular Waves-induced Seabed Dynamic Responses around Submerged Breakwater (규칙파동장하 잠제 주변지반의 동적거동에 관한 수치해석)

  • Lee, Kwang-Ho;Ryu, Heung-Won;Kim, Dong-Wook;Kim, Do-Sam;Kim, Tae-Hyung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.3
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    • pp.132-145
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    • 2016
  • In case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be generated significantly due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result from decrease in the effective stress. Under the seabed liquefaction occurred and developed, the possibility of structure failure will be increased eventually. In this study, to evaluate the liquefaction potential on the seabed quantitatively, numerical analysis was conducted using the expanded 2-dimensional numerical wave tank model and the finite element elasto-plastic model. Under the condition of the regular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated.

Numerical Analysis on Liquefaction Countermeasure of Seabed under Submerged Breakwater Using Concrete Mat Cover (for Irregular Waves) (콘크리트매트 피복을 이용한 잠제하 해저지반에서의 액상화 대책공법에 관한 수치해석 (불규칙파 조건))

  • Lee, Kwang-Ho;Ryu, Heung-Won;Kim, Dong-Wook;Kim, Do-Sam;Kim, Tae-Hyung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.1
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    • pp.20-35
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    • 2017
  • In the case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be significantly generated due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result of the decrease in the effective stress, and eventually the possibility of structure failure will be increased. The study of liquefaction potential for regular waves had already done, and this study considered for irregular waves with the same numerical analysis method used for regular waves. Under the condition of the irregular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated and their results were compared with those of the regular wave field to evaluate the liquefaction potential on the seabed quantitatively. Although present results are based on a limited number of numerical simulations, one of the study's most important findings is that a safer design can be obtained when analyzing case with a regular wave condition corresponding to a significant wave of the irregular wave.

Numerical Analysis on Wave Characteristics around Submerged Breakwater in Wave and Current Coexisting Field by OLAFOAM (파-흐름 공존장내 잠제 주변에서 OLAFOAM에 의한 파랑특성의 수치해석)

  • Lee, Kwang-Ho;Bae, Ju-Hyun;An, Sung-Wook;Kim, Do-Sam;Bae, Kee Seung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.6
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    • pp.332-349
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    • 2016
  • OLAFOAM is the powerful CFD code and is an expanded version of $OpenFOAM^{(R)}$, for wave mechanics simulation. The $OpenFOAM^{(R)}$ does provide many solvers to correspond to each object of the numerical calculation in a variety of fields. OLAFOAM's governing equation bases on VARANS (Volume-Averaged Reynolds-Averaged Navier-Stokes) equation, and the finite volume method is applied to numerical techniques. The program is coded in C++ and run on the Linux operating system. First of all, in this study, OLAFOAM was validated for 1) wave transformation inside porous structure under bore and regular wave conditions, 2) wave transformation by submerged breakwater under regular wave condition, and 3) regular wave transformation and resultant vertical velocity distribution under current by comparison with existing laboratory measurements. Hereafter, this study, which is almost no examination carried out until now, analyzed closely variation characteristics of water surface level, wave height, frequency spectrum, breaking waves, averaged velocity and turbulent kinetic energy around porous submerged breakwater in the wave and current coexisting field for the case of permeable or impermeable rear beach. It was revealed that the wave height fluctuation according to current direction(following or opposing) was closely related to the turbulent kinetic energy, and others.

Irregular Waves-Induced Seabed Dynamic Responses around Submerged Breakwater (불규칙파동장하 잠제 주변지반의 동적거동에 관한 수치해석)

  • Lee, Kwang-Ho;Ryu, Heung-Won;Kim, Dong-Wook;Kim, Do-Sam;Kim, Tae-Hyung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.4
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    • pp.177-190
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    • 2016
  • In case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be generated significantly due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result from decrease in the effective stress. Under the seabed liquefaction occurred and developed, the possibility of structure failure will be increased eventually. Lee et al.(2016) studied for regular waves, and this study considered for irregular waves with the same numerical analysis method used for regular waves. Under the condition of the irregular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated and their results were compared with those of the regular wave field to evaluate the liquefaction potential on the seabed quantitatively. Although present results are based on a limited number of numerical simulations, one of the study's most important findings is that a more safe design can be obtainable when analyzing case with a regular wave condition corresponding to a significant wave of irregular wave.

The Effect of A Submerged Plate Breakwater to Sea Water Exchange (잠재평판에 의한 해수 순환 효과)

  • 이정렬
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 1996.10a
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    • pp.76-79
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    • 1996
  • 최근 주로 일본 해안공학자인 Hattori와 Matsumoto(1977), Aoyama 등(1900), Yu 등(1990)에 의하여 잠재평판(submerged plate)이 항만의 외곽 구조물로서 파랑 에너지의 저감에 미치는 영향에 대한 연구가 수행되어 왔다. Hattori와 Matsumoto(1977)에 의하면 장파에 대하여 평판구조물은 방파제로서의 역할을 못하는 것으로 판명됐으며 그리고 Yu 등(1990)의 실험결과에 의하면 평판의 길이가 전수심에 의한 파장과 동일하고 핑판위의 수심이 전수심의 0.2인 경우 0.8초의 단파에 대하여 투과율이 30%까지 감소되었다. (중략)

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