• 한국해안해양공학회지
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• 제13권2호
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• pp.100-108
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• 2001

지진해일 또는 조석과 같은 장파의 거동을 모의할 때 해안선의 위치는 파랑의 움직임에 따라 연속적으로 이동된다. 따라서, 수치모형에 이를 효과적으로 반영하기 위해서는 해안선을 파랑에 따라 이동시켜야 한다. 본 연구에서는 경사지형을 계단지형으로 단순화한 이동경계조건을 이용하여 해일이나 조석에 의한 최대범람구역을 결정한다. 이동경계조건을 이용하여 특정지역의 최대범람구역을 결정한 후 기존의 관측자료와 비교하였으며, 결정된 최대범람구역은 기존의 자료와 잘 일치한다.

• 한국해안해양공학회지
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• 제19권3호
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• pp.222-227
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• 2007

심해에서 생성된 최극해파가 파랑과 상호작용하는 현상에 대한 연구를 수행하였다. 이러한 파랑은 분산집중을 이용하여 산정하였다. 이러한 과정은 선형 및 비선형 방정식의 해를 구하여 얻을 수 있다. 상호작용에서 비선형성의 역할을 강조하였다.

• 한국해안해양공학회지
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• 제1권1호
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• pp.63-70
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• 1989

단일 및 2개의 연직 불투과성 구조물이 해역에 설치되어 있는 경우 파랑의 회절 및 상호간섭 효과를 일정요소를 사용한 경계요소법에 의해 수치 해석하였다. 파랑은 2차원 선형 회절파 이론으로부터 해석하였으며 구조물 경계상에서 뿐만 아니라 구조물 주위에서의 회절계수를 계산하였다. 본 계산의 신뢰도를 검증하기 위하여 기존의 해석결과와 비교하였으며 대체로 잘 일치하고 있음을 알 수가 있었다.

• 한국해안해양공학회지
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• 제5권3호
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• pp.232-239
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• 1993

연안역에서의 파동이 오염원의 확산에 미치는 영향에 관한 연구를 수행하였다. 천해근사를 사용하여 기존의 확산방정식을 수심에 관하여 적분함으로써, 임의의 진폭을 갖는 장파조건 및 임의의 흐름조건에 대하여 적용가능한 방정식을 유도하였다. 수립된 방정식을 사용하여 장파가 오염원의 농도에 영향을 미치는 여러 경우에 대하여 고찰하였다.

• 대한조선학회지
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• 제23권3호
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• pp.1-9
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• 1986

Herein the dynamic response of an axisymmetric buoy to regular wave is studied within linear potential theory. The buoy has a particular geometry so that it should experience minimum wave-exiting force on the vertical direction at a precribed wave number in water of finite depth. Invoking the Green's theorem a velocity potential is generated by distributing pulsating sources and doublets on the immersed surface of the buoy at its mean position. Hydrodynamic forces and moments are obtained approximately by summation of the products of linear pressure and directional mesh area over the immersed surface. Model tests are carried out to measure the wave-exciting forces, hydrodynamic forces and motion responses. The experimental results in general agree fairly well with the numerical ones. From the analytical and experimental works it is found that the pitching motion and its coupling effect affect significantly the motion characteristics of the freely-floating axisymmetric buoy in regular waves.

• 대한조선학회논문집
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• 제40권2호
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• pp.11-20
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• 2003

In this paper, the high-order spectral/boundary-element method is developed to calculate the 3-dimensional water waves generated by a submerged body. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated Tn time-domain. Three-dimensional free-surface flows generated by a submerged sphere which is moving under the free-surface are calculated. Through example calculations, nonlinear effects on free-surface profiles and hydrodynamic forces are shown. Comparisons with others' results show good agreements.

• 한국분무공학회지
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• 제9권4호
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• pp.1-8
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• 2004

Breakup characteristics of liquid sheets formed by the impingement of two water jets, such as a breakup length and a breakup wavelength of sheet, were investigated as increasing the injection velocity up to 30m/s and the ambient gas pressure up to 4.0MPa. While round edged orifices formed a laminar sheet which has no waves on the sheet when the injection velocity is low, sharp edged orifices formed a turbulent sheet which has impact waves irrespective of the injection velocity. Thus we compared the differences of breakup characteristics between them. The results showed that the aerodynamic force significantly affects the breakup of laminar sheet when the gas based Weber number is higher than unity, It was also found that the turbulent sheets have three breakup regimes, i.e. expansion regime, wave breakup regime and catastrophic breakup regime according to the gas based Weber number.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.173-179
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• 2004

Breakup characteristics of liquid sheets formed by the impingement of two water jets, such as a breakup length and a breakup wavelength of sheet, were investigated as increasing the injection velocity up to 30m/s and the ambient gas pressure up to 4.0㎫. While round edged orifices formed a laminar sheet which has no waves on the sheet when the injection velocity is low, sharp edged orifices formed a turbulent sheet which has impact waves irrespective of the injection velocity. Thus we compared the differences of breakup characteristics between them. The results showed that the aerodynamic force significantly affects the breakup of laminar sheet when the gas based Weber number is higher than unity. It was also found that the turbulent sheets have three breakup regimes, i.e. expansion regime, wave breakup regime and catastrophic breakup regime according to the gas based Weber number.

• 대한조선학회지
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• 제11권1호
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• pp.17-26
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• 1974

In this paper, authors investigate and analyze the effects of the anti-rolling tank which are calculated in accord with the tank damping coefficients by the computer, and which are represented with both the tank water's saturating state and the normal state in the irregular waves by analog computer. As the results of these studies, we immediately find that the tank optimum damping coefficient $b_{to}$, is 0.3877 due to calculating $\mu$-values, analyzing and comparing inclinations of $\mu$-values, and that although a nonlinear elements are included in the response character of the ship-tank system, the output is no longer Gaussian distribution, even when the sea waves are considered as Gaussian, and can not be expressed by the spectral forms which premise the superposition theory.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권1호
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• pp.1-13
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• 2014

A new 5-MW floating offshore wind turbine moored by a spring-tensioned-leg was proposed for installation in about 50m water depth. Its substructure is a platform of the inverted conical cylinder type with massive ballast weight plate at the bottom. A 1:128 scale model was built for the preliminary engineering development. The model tests in waves and wind were carried out to estimate motion characteristics of this platform in the Ocean Engineering Wide Tank of the University of Ulsan. Its motions were measured and the RAOs were compared. The proposed floating offshore wind turbine showed a good stability and decent responses in waves, wind and operation of the wind turbine.