• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.4
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• pp.180-190
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• 2018

The preliminary study was carried out to utilize the rolling porous pendulum plate as a hybrid system combining blocking and extracting of wave energy. The Galerkin method suggested by Porter and Evans (1995) was used to solve the diffraction and radiation problems to obtain reflection and transmission coefficient, roll displacement, extracted power. The Galerkin method provides better convergence than the matched eigenfunction expansion method (MEEM), which improves the accuracy of the analytical solution even if the CPU time is shorter. The porous plate can not be said to be more effective than the impermeable plate in terms of wave energy extraction and wave blocking, but it has the advantage of reducing the wave load and exchanging seawater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.4
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• pp.313-320
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• 1995

A numerical analysis on the wave deformation in the shallow water region is performed for the case of two intersecting wave trains of the same frequency on uniformly sloping beaches. This model is based on the consideration of wave energy balance and wave action conservation, and iteratively solved the set of conservation equations of both mass and horizontal momentum. Using the computed results, the wave deformations in accordance with the variation of the parameters luck as incident wave angie and wave height in deep water which influences the variation of wave hight and mean water level under the intersecting wave trains in the shallow water region. are considered.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.10a
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• pp.83-86
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• 2003

선박은 근본적으로 파랑이 향상 존재하는 해상에서 운항하게 되므로 파랑 중에서의 선체운동 여객, 승무원, 화물 및 선박 자체의 안전과 밀접한 관계를 가지게 된다. 뿐만 아니라 선박의 운동은 해상에서의 각종 활동과 임무수행의 정도를 결정하는 주요한 인자가 되고 있다. 횡동요(Rolling)는 6 자유도 운동 가운데에서 가장 중요한 운동이며, 선박들이 근본적으로 횡동요에 대하여 낮은 감쇠특성을 갖고 있기 때문에 안정성 측면에서 볼 때에 가장 많이 제어되어 왔다. (중략)

• The Journal of the Petrological Society of Korea
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• v.19 no.2
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• pp.157-165
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• 2010

The age unknown Ogcheon metasedimentary rocks and the Jurassic Ogcheon granite (Jocgr) intruding it are distributed in the Ogcheon area, which is located in the central part of the Ogcheon Belt, Korea, This paper newly examines the timing of Honam shearing on the basis of the microstructural researches on time-relationship between the crenulation of Ogcheon metasedimentary rocks and the contact metamorphism by the intrusion of Jocgr. The D2 crenulation phase, which is defined by the microfolding of the S1 foliation in the metasedimentary rocks, is divided into two sub-phases. The one is a sub-phase of Early crenulation (D2a) which is included within old andalusite porphyroblasts, and the other is that of Late crenulation (D2b) which warps around the old andalusite. But they show the same dextral shear sense, the axial planes parallel to each other, and a single crenulation at outcrop scale. The contact metamorphism of andalusite-sillimanite type by the Jocgr occurred during the inter-phases of D2a and D2b, and crystallized the old andalusite masking the D2a crenulation and fibrous sillimanites replacing the D2a crenulation-forming muscovites. New andalusite porphyroblasts synkinematically grew in pressure shadows around the old andalusite or in its outermost mantles during the early stage of the D2b. The D2b occurred still continuously after the growth of the andalusite ceased (= later stage of the D2b). It indicates that the D2b occurred continuously during the period when the Ogcheon granite was still hot and cool. From this study, the crenulation history of Ogcheon metasedimentary rocks and the timing of Honam shearing would be newly established and reviewed as follows. (1) Early Honam shearing; formative period of Early crenulation, (2) main magmatic period of Jurassic granitoids; growth of the old andalusite and fibrous sillimanite by the intrusion of Jocgr, (3) main cooling period of Jurassic granitoids; formative period of Late crenulation related to Late Honam shearing, growth of the new andalusite in the early stage of D2b. Thus, this study proposes that the Honam shear movement would occur two times at least before and after the intertectonic phase which corresponds to the main magmatic period of Jurassic granitoids.

• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.401-409
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• 2013

In the present study, numerical analysis was performed for hydrodynamic motion and structural performance on four different concrete floating structures, which have same cross-section but different length. The hydrodynamic analysis of floating structures is carried out using ANSYS AQWA with the different 34 wave load on regular wave period from three seconds to ten seconds in 35 m water depth. In order to evaluate structural performance of floating structures under the critical wave load which obtained from hydrodynamic analysis. The integrated analysis is also carried out through the mapping method, which can directly connect the wave-induced hydraulic pressure obtained form ANSYS AQWA to Finite Element Model in ANSYS Mechanical. As a results of this study, the hydrodynamic motion of floating structures is decreased as the length of structure increased. It means that the effect of wave-structure interaction is strongly dependent on the relationship between a wave period and a length of structure. Moreover, it is found that tension stress on bottom slab of floating structure is occurred by the critical wave load, the sectional force is not influenced by length of a structure.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2002.08a
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• pp.62-65
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• 2002

파랑은 주로 먼바다에서 바람에 의해 생성되어 육지로 전파해오면서 천수, 굴절, 회절, 반사, 부서 짐 등의 여러 가지 변형의 과정을 거친다. 이러한 파랑의 변형을 예측하는 한 방법은 비압축성 유체와 비회전류의 연속방정식인 Laplace 방정식을 지배 방정식으로 하고 해수면에서의 운동학적 경계조건과 동역학적 경계 조건, 그리고 바닥에서의 운동학적 경계조건을 적용하여 해를 구한다. (중략)

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1991.07a
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• pp.30-35
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• 1991

해저가 완만하게 변하는 해역 위를 지나는 파랑의 반사는 무시할 수 있으며 이에 대한 파랑계산 방법으로는 굴절 모델 (서 등, 1989)과 포물형 근사식 모델(서, 1990b)을 들 수 있다. 그러나 해저의 변화가 심해 상당량의 파랑에너지가 반사되는 경우에는 파랑 운동을 지배하는 원시 방정식인 Laplace을 사용하여야 한다.(중략)

• Journal of the Society of Naval Architects of Korea
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• v.30 no.1
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• pp.45-64
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• 1993

This paper dealt with the application of a numerical method developed by the authors using the matching method proposed in the previous paper on "The Nonlinear motions of cylinders(I)[16]", and Cauchy's theorem to the problems associated with hydrodynamic forces acting on a heaving cylinders translating in a calm water and also motions of cylinders in waves. In spectral method. body boundary condition in submerged case is satisfied exactly but one in floating case is not satisfied exactly. In the numerical code developed here, the boundary condition at the free-surface and body surface is satisfied exactly at its instaneous position. It is of interest to note that the present scheme could be applied to a free-surface-piercing body without experiencing a difficulty in the numerical convergence. The computed results are compared with other results([6], [12]).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.3
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• pp.183-191
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• 2002

In general, the salient features of the floating breakwater have excellent regulation of sea-water keeping the marine always clean, up and down free movement with the incoming and outgoing tides, capable of being installed without considering the geological condition of sea-bed at any water depth. This study discusses the three dimensional wave transformation of the floating breakwater moored by piers, and its dynamic response numerically. Numerical method is based on the boundary integral method and eigenfunction expansion method. It is known that pier mooring system has higher absorption of wave energy than the chain mooring system. Pier mooring system permit only vertical motion (heaving motion) of floating breakwater, other motions restricted. It is assumed in the present study that a resistant force as friction between piers and floating pontoon is not applied far the vertical motion of the floating breakwater. According to the numerical results, draft and width of the floating breakwater affect on the wave transformations greatly, and incident wave of long period is well transmitted to the rear of the floating breakwater, And the vertical motion come to be large for the short wave period.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.357-359
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• 2007

해양에너지원 중에서 파랑은 모든 해역에 폭넓게 분포하므로 가용에너지원이 풍부하고 에너지를 회수하기 위한 장치를 설치할 수 있는 해역 또한 광범위하며 반도의 지형을 지닌 우리나라의 연안 해역에 대규모로 활용이 가능한 에너지 자원중 하나이다. 본 연구는 새로운 방식인 파력발전용 횡류형터빈인 케이슨 내장형 횡류터빈을 개발하기에 앞서 파랑수조의 왕복운동을 CFD해석을 통하여 구현하는 것이다.