• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 Asia Navigation Conference
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• pp.95-104
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• 2006

A floating-type wave power pump is a device which sends air into water by using wave power. The floating-type wave power pump has the new configuration composed of a curved surface reflection board, a slope, and phase plates. As a result of a water-tank experiment it turned out that the floating-type wave power pump with a curved surface reflection board and a slope raised power and efficiency in the wide wavelength waves. The result of a marine experiment was also preferable. The floating-type wave power pump sends air into the sea by using wave power, so it can be used for the improvement of marine environment. In addition, the floating body constituted of a curved surface reflection board, a slope, and phase plates, is effective as a device to utilize the energy of a wave. Therefore, it can be widely used for a wave power generation, pumping up deep seawater.

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 1997년도 정기학술강연회 발표논문 초록집 Annual Meeting of Korean Society of Coastal and Ocean Engineers
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• pp.39-44
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• 1997

As wind waves generated in deep water approach nearshore zone, they experience various physical phenomena caused by bathymetric variations, nonlinear interactions among different wave components and interferences with man-made coastal structures. Among these, the bathymetric variations may play a significant role in the change of wave climate. The accurate calculation of reflection and transmission coefficients of incident waves over a bottom topography is indispensible for the proper and economical design of coastal structures. (omitted)

• 한국해안·해양공학회논문집
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• 제28권6호
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• pp.383-396
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• 2016

본 연구에서는 파랑과 흐름이 공존하는 해역에서 수위변화 및 흐름효과 고려 유무에 대하여 파랑모델을 수행하여 그 결과를 비교하였다. 해수유동장은 RIAMOM 모델 결과를 적용하였으며 파랑모델은 SWAN모델을 적용하였다. 바람자료는 ECMWF, NCEP 및 JMA의 3가지에 대하여 관측자료를 비교적 잘 재현하는 JMA 자료를 적용하였다. 수치모의는 2016년 1월~8월까지 8개월간 수행하였으며, 각 경우에 대하여 관측자료와의 비교를 위하여 2.5 m이상의 고파랑 기간에 대해 파고변화를 검토하였다. 분석결과, 수심이 깊은 파랑관측부이 정점에서는 수위/흐름효과를 고려할 경우 파고변화가 크지 않게 나타났으나, 수심이 얕은 비교 정점에서는 수위/흐름효과의 고려 여부에 따라 5~10%의 유의미한 파고변화가 나타났다.

• 산업기술연구
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• 제8권
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• pp.3-11
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• 1988

Shock pressure of wave breaking on vertical wall is studied experimentally with beaches, which have four different slopes (1/4.02, 1/7.05, 1/10, 1 /13.5). This results is summerized as follows: 1. Maximum impact presures are occured where the wave break directly on the wall rather than breaking in front of the wall. 2. Deep water steepness, and the beach slope are the two Quantities governing the magnitude and location of maximum dimensionless impact pressure from wave breaking directly on the wall, also, the greatest pressure is produced with a beach slope of 1/10. 3. This study is clearly shown that the location of maximum pressure can be presented above still water level under respectively experimental condition. The dimensionless elevation of maximum Pressure is greatest on a beach slope of 1/10.

• 대한조선학회지
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• 제24권1호
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• pp.9-16
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• 1987

The second-order steady horizontal force and vertical moment are derived for a freely-floating body in water of finite depth. Momentum relations are used in terms of the Kochin function in the fluid region far from the body. The general results look very similar to those for deep water. The water depth is formally reflected in terms of the ratio between the phase and group velocities of incident waves. Computations are made for a Series 60 hull($C_B=0.6$) and are compared with the corresponding results of deep water. It is shown that the vertical drift moment for slender ships becomes completely free from water depth when the wave-ship length ratio is taken as parameter.

• Ocean Systems Engineering
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• 제8권3호
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• pp.313-327
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• 2018

Meeting the touchdown point (TDP) target box is one of the challenges during catenary riser installation, especially for deep water or ultra-deep water riser systems. TDP location mismatch compared to the design can result in variation of riser configuration, additional hang-off misalignment, and extra bending loads going into the hang-off porch. A good understanding of the key installation parameters can help to minimize this mismatch, and ensure that the riser global response meets the design criteria. This paper focuses on investigating the potential factors that may affect the touchdown point location, and addressing the challenges both in the design stage and during installation campaign. Conventionally, the vessel offset and current are the most critical factors which may affect the TDP movement during installation. With the offshore exploration going deeper and deeper in the sea (up to 10,000ft), other sources such as the seabed slope and seabed soil stiffness are playing an important role as well. The impacts of potential sources are quantified through case studies for steel catenary riser (SCR) and lazy wave steel catenary riser (LWSCR) in deep water application. Investigations through both theoretical study and numerical validation are carried out. Furthermore, design recommendations are provided during execution phase for the TDP mismatch condition to ensure the integrity of the riser system.

• Ocean Systems Engineering
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• 제10권4호
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• pp.399-414
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• 2020

A floating bridge is an innovative solution for deep-water and long-distance crossing. This paper presents a curved floating bridge's dynamic behaviors under the wind, wave, and current loads. Since the present curved bridge need not have mooring lines, its deep-water application can be more straightforward than conventional straight floating bridges with mooring lines. We solve the coupled interaction among the bridge girders, pontoons, and columns in the time-domain and to consider various load combinations to evaluate each force's contribution to overall dynamic responses. Discrete pontoons are uniformly spaced, and the pontoon's hydrodynamic coefficients and excitation forces are computed in the frequency domain by using the potential-theory-based 3D diffraction/radiation program. In the successive time-domain simulation, the Cummins equation is used for solving the pontoon's dynamics, and the bridge girders and columns are modeled by the beam theory and finite element formulation. Then, all the components are fully coupled to solve the fully-coupled equation of motion. Subsequently, the wet natural frequencies for various bending modes are identified. Then, the time histories and spectra of the girder's dynamic responses are presented and systematically analyzed. The second-order difference-frequency wave force and slowly-varying wind force may significantly affect the girder's lateral responses through resonance if the bridge's lateral bending stiffness is not sufficient. On the other hand, the first-order wave-frequency forces play a crucial role in the vertical responses.

• 한국가시화정보학회지
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• 제18권3호
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• pp.14-22
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• 2020

An experiment, in the cases that satisfies deep water condition, has been performed to observe the strongly nonlinear sloshing flow in a rectangular tank. A variety of parametric study on oscillating frequency and amplitude was conducted and we found that two types of wave motions, sloshing wave and Faraday wave, could be persisting simultaneously even in horizontal sloshing problem. Moreover, it is observed both of symmetric and skewed symmetric Faraday wave exist. A comprehensive explanation is given to the generation mechanism of those waves and how to interact among them.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.557-562
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• 2004

A surface-piercing barrier model is presented for understanding morphological development in the sheltered region and investigating the main factors causing the severe accumulation. Surface-piercing structures like vertical barriers, surface docks and floating breakwaters are recently favored from the point of view of a marine scenario since they do not in general partition the natural sea. The numerical solutions are compared with experimental data on wave profiles and morphological change rates within a rectangular harbor of a constant depth protected by surface-piercing thin breakwaters as a simplified problem. Our numerical study involves several modules: 1) wave dynamics analyzed by a plane-wave approximation, 2) suspended sediment transport combined with sediment erosion-deposition model, and 3) concurrent morphological changes. Scattering waves are solved by using a plane wave method without inclusion of evanescent modes. Evanescent modes are only considered in predicting the reflection ratio against the vertical barrier and energy losses due to vortex shedding from the lower edge of plate are taken into account. A new relationship to relate the near-bed concentration to the depth-mean concentration is presented by analyzing the vertical structure of concentration. The numerical solutions were also compared with experimental data on morphological changes within a rectangular harbor of constant water depth. Through the numerical experiments, the vortex-induced flow appears to be not ignorable in predicting the morphological changes although the immersion depth of a plate is not deep.

• 대한조선학회지
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• 제20권2호
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• pp.37-42
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• 1983

This paper presents a procedure within the framework of linear potential theory for predicting the lateral drifting forces on a cylinder floating on the free surface of a finite depth water. The disturbance of a regular incident wave caused by the presence of the floating body is represented by the sum of the diffracted and radiated wave potentials, which are determined by using Green's theorem. The lateral drifting forces are calculated by use of momentum theorem, and the scattered waves are expressed in their asymptotic forms. The computed lateral drifting forces on a Lewis form cylinder(b/T=1.25, $\sigma$=0.95) for water depth to draft ratio of 5.0 are compared with the Kyozuka's experimental results for a deep water, and found to be in good agreement. The water depth effects on drifting forces of the same model are also calculated.