• 대한조선학회논문집
• /
• 제41권3호
• /
• pp.22-27
• /
• 2004

Waveheight attenuation efficiencies of floating breakwaters in water of finite depth for a VLFS are studied numerically in accordance with the two body radiation-diffraction problem. Four different forms of the breaker are tested with a solid VLFS. The radiation-diffraction wave elevations between the breakwater and the VLFS are predicted directly instead of the far-field transmission-reflection coefficients of the breakwater.

• 한국방재학회 논문집
• /
• 제11권1호
• /
• pp.93-99
• /
• 2011

본 연구에서는 단독형 및 2열형(multi-arranged (2 pieces)), 3열형(multi-arranged) 부유식방파제에서의 구조물간 거리와 흘수, 형상을 변화시키고 파의 주기와 파형경사를 변화시키며, 다양한 변수변화에 따른 영향을 분석하였다. 부유식방파제의 흘수변화는 전달계수에 직접적인 영향을 주며, 비교적 장주기에 해당하는 조파조건에선 단독형과 2열형 부유식방파제보다 3열형 구조에서 높은 방파효율을 나타내었다. 수리모형실험의 결과 검증을 위하여 수치모형과 동일한 조건하에 실험을 하고 LDV시스템을 이용하여 각 부유식방파제에서의 유동장을 측정하였으며, 수리모형실험을 통하여 그에 따른 전달계수을 분석하였다.

• 한국해양공학회지
• /
• 제5권2호
• /
• pp.16-30
• /
• 1991

A numerical procedure is described for predicting the dynamic responses of combined systems of floating breakwaters and huge offshore structures supported by a large numer of the floating bodies in waves. The hydrodynamic interactins among tatal floating bodies are taken into account in their exact form within the context of linear potential theory. Wave control effects are discussed with both hydrodynamic interactions and hydrodynamic-structure interaction effects. The method presented is applicalbe to combined systems of floating breakwaters and huge structures for ocean space utilization for which a number of practical uses are seen in the future.

• 한국해양공학회지
• /
• 제5권2호
• /
• pp.156-156
• /
• 1991

A numerical procedure is described for predicting the dynamic responses of combined systems of floating breakwaters and huge offshore structures supported by a large numer of the floating bodies in waves. The hydrodynamic interactins among tatal floating bodies are taken into account in their exact form within the context of linear potential theory. Wave control effects are discussed with both hydrodynamic interactions and hydrodynamic-structure interaction effects. The method presented is applicalbe to combined systems of floating breakwaters and huge structures for ocean space utilization for which a number of practical uses are seen in the future.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2017년도 학술발표회
• /
• pp.514-514
• /
• 2017

Floating breakwaters were treated as solid bodies without any perforation in previous studies. In this study, however, a floating breakwater is perforated to allow the partial absorption of the energy produced by incident waves and an air chamber is placed in the upper part to control the breakwater draft. A series of laboratory experiments for a floating breakwater installed with a mooring system are carried out. In general, a mooring system can be classified by the number of mooring points, the shape of the mooring lines, and the degree of line tension. In this study, a four-point mooring is employed since it is relatively easier to analyze the measured results. Furthermore, both the tension-leg and the catenary mooring systems have been adopted to compare the performance of the system. In laboratory experiments, the hydraulic characteristics of a floating breakwater were obtained and analyzed in detail. Also, a hydraulic model test was carried out on variable changes by changing the mooring angle and thickness of perforated wall. A hydraulic model was designed to produce wave energy by generating a vortex with the existing reflection method. Analysis on wave changes was conducted and the flow field around the floating breakwater and draft area, which have elastic behavior, was collected using the PIV system. From the test results the strong vortex was identified in the draft area of the perforated both-sides-type floating breakwater. Also, the wave control performance of the floating breakwater was improved due to the vortex produced as the tension in the mooring line decreased.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2001년도 학술발표회 논문집(II)
• /
• pp.1133-1138
• /
• 2001

The focus of this paper is on the numerical investigation of obliquely incident wane interactions with a system composed of full submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing. The fully submerged systems allow surface and bottom clearances to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of fille second kind) tat satisfy the Helmholz governing equation. Using this computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, clearances. spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters call, if it is properly tuned to the coming waves, have good performances ill reflecting the obliquely incident waves over a tilde range of wave frequency and headings.

• 한국해양공학회지
• /
• 제18권6호
• /
• pp.29-36
• /
• 2004

Floating breakwaters have been recently studied to reduce the transmission ratio of wave energy. The numerical study shows how wave pressure and stress act on the rectangular floating breakwater under various regular wave conditions. In order to evaluate hydrodynamic pressure on the floating breakwater, the infinite element is applied to the linear wave diffraction and radiation problems. SAP2000, a structural analysis program, is used to evaluate stress on the floating breakwater.

• 한국방재학회 논문집
• /
• 제10권6호
• /
• pp.175-183
• /
• 2010

본 연구에서는 LDV시스템을 이용하여 부유식 방파제 주변의 유동장의 변화를 수리모형실험을 통해 분석하였다. LDV시스템은 유체의 유속을 측정하기 위해 다양한 수리모형실험에서 폭넓게 사용되어왔다. LDV시스템을 이용하면 측정시간이 오래 걸리는 단점이 있지만, 측정한 자료를 가공하지 않고 정확한 유속장을 제시할 수 있다는 장점이 있다. 방파제의 형상과 흘수를 달리하여 수리모형실험을 수행하였으며, 유동장과 와류의 상관관계를 분석하였다. 또한, 연직 2차원 Navier-Stokes 방정식 모형을 이용하여 수치모형실험을 수행하였으며, 수치모형실험 결과와 수리모형실험 결과를 비교분석하였다.

• 한국해양공학회지
• /
• 제15권2호
• /
• pp.11-21
• /
• 2001

The focus of this paper is on the numerical investigation of obliquely incident wav interactions with a system composed of fully submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing between two systems. The fully submerged two systems allow surface and bottom gaps to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of the second kind) that satisfy the Helmholz governing equation in fluid domains. A boundary element program for three fluid domains based on a discrete membrane dynamic model and simple source distribution method is developed. Using this developed computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, gaps, spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters can, if it is properly tuned to the coming waves, have good performances in reflecting the obliquely incident waves over a wide range of wave frequency and headings.

• 한국해양공학회지
• /
• 제19권2호
• /
• pp.19-28
• /
• 2005

The present paper outlines the numerical investigation of the incident wave interactions with fully submerged and floating dual double hull pontoon/vertical porous membrane breakwaters. Two dimensional five fluid-domains hydro-elastic formulation was carried out in the context of linear wave body interaction theory to study the wave interaction with the double hull of pontoon-membranes. The submerged circular pontoon is consisted of double hulls, which is filled with water in the void space between the outer structure and inner solid buoyant structure. Hydrodynamic characteristics of the proposed system with dual floating double-hull-pontoons filled with water have been studied numerically for the various incident waves. This study is a beginning stage research for the dual double hull porous pontoons/vertical porous membranes breakwaters which is ideally designed in order to suppress significantly the transmitted and reflected waves simultaneously.