• 한국항해항만학회지
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• 제28권8호
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• pp.745-751
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• 2004

본 연구근 신 등(2004)의 후속연구로서, 연근해의 상세 공간 분할의 계산에 적용하여 높은 정밀도의 파랑 추산이 가능한 수정 WAM cycle 4모형을 토대로 2003년 9월 한 달 동안의 파랑을 상세히 추산하고, 태풍 ‘매미’가 야기한 우리나라 남해안 일대의 극한파랑 특성을 분석한 것이다 계산된 파랑 제원은 이어도 해양종합기지에서 관측된 파랑 제원과의 비교를 통하여 모형의 정밀도를 확인하였고, 우리나라 남해안주요 4개 지점의 전면 해상에 대해서는 1시간 간격의 파랑 추산 결과의 분석을 통해 태풍 ‘매미’가 야기한 외해 극한파랑을 다음과 같이 추산하였다. 1) 제주도 서편 차귀도 전면 해상； 2003년 9월 12일 16시에 최대 유의파고 7.41m, 평균 주기 13.6s, 평균 파향 6.4$^{\circ}$, 2) 마산만 입구； 12일 21시에 최대 유의파고 12.50m, 평균 주기 13.65s, 평균 파향 1.2$^{\circ}$, 3) 부산 수영만 전면 해상； 12일 22시에 최대 유의파고 13.85m, 평균 주기 13.81s, 평균 파향 0.2$^{\circ}$, 4) 울산항 전면 해상； 12일 23시에 최대 유의파고 11.00m, 평균 주기 13.25s, 평균 파향 $2.8^{\circ}$.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.309-316
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• 2003

In this paper, The statistical properties of ocean waves in the sea area of Hong-do, Korea are examined based on 1998-2002's wave data from a directional wave buoy. Wave data aquisition rate, mean wave heights, frequency of wave direction are summarized. Wave height and period scatter diagrams and n-years return period wave heights are estimated. Wave periods of maximum wave heights are also estimated. Large amplitude wave characteristics during the typhoon Prapiroon in 2000, Rusa in 2002 are also examined.

• 한국해양공학회지
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• 제29권4호
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• pp.300-308
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• 2015

With the increases in oil and gas prices, and energy consumption, drillship construction has increased during the last decade. A drillship using a dynamic positioning (DP) system to maintain its position and heading angle during drilling operations. In addition, a drillship is equipped with a moonpool structure to allow its drilling systems to be operated in the midship section. A drillship for the North Sea is specially designed to endure harsh environmental loads. For safe operation in the North Sea, the drillship should have good motion response and robust hull strength. A break water should be considered on the bow and side deck to prevent the green water on deck phenomenon from incoming waves. In addition, the moonpool should be designed to reduce the speed loss and resonance motion. In this study, the hydrodynamic characteristics of a drillship for the North Sea were examined in relation to the motion, wave loads, green water, and moonpool resonance in the initial design stage.

• 대한조선학회논문집
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• 제29권1호
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• pp.113-122
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• 1992

선박소음을 예측하는 과정중에서 고체소음 전달해석은 직접적으로 예측결과의 정도에 영향을 미치고 있다. 이에 대한 계산 방법으로서 경험식이 그 간편성 때문에 자주 사용되고 있지만 자체의 한계성 때문에 이론적 해석방법(Wave guide theory, SEA등)들에 대한 연구가 선박음향학 분야에서 꾸준히 수행되어 왔다. 본 연구에서는 SEA를 이용하여 22개의 plate로 구성된 선체구조의 단순모델을 대상으로 고체소음 전달손실에 대한 이론적 계산 및 실험적 산정을 수행하였다. 계산치와 실험치의 비교결과는 3 dB이내의 좋은 일치를 보여 주었다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.624-637
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• 2019

A semi-submersible offshore platform always operates under complex weather conditions, especially wind and waves. It is vital to analyze the structural dynamic responses of the platform in short-term sea states under the combined wind and wave loads, which touches upon three following work. Firstly, a derived relationship between wind and waves reveals a correlation of wind velocity and significant wave height. Then, an Improved Mixture Simulation (IMS) method is proposed to simulate the time series of wind/waves accurately and efficiently. Thus, a wind-wave scatter diagram is expanded from the traditional wave scatter diagram. Finally, the time series of wind/wave pressures on the platform in the short-term sea states are converted by Workbench-AQWA. The numerical results demonstrate that the proposed numerical methods are validated to be applicable for wind and wave simulations in structural analyses. The structural dynamic responses of the platform members increase with the wind and wave strength. In the up-wind and wave state, the stresses on the deck, the connections between deck and columns, and the connection between columns and pontoons are relatively larger under the vertical bending moment. These numerical methods and results are wished to provide some references for structural design and health monitoring of several offshore platforms.

• Journal of the korean society of oceanography
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• 제34권1호
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• pp.22-35
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• 1999

The response of the tidal waves to friction effect is investigated in terms of deformation of Kelvin and Poincare modes, The 1st Poincare mode does not exist over the low frequency region less than the critical frequency of omega ${\omega}$${\sqrt{2f}}$, with ${\gamma}$/f=0.0, but the mode comes to exist in the presence of friction. When friction exists and its magnitude increases, the wave number increases, indicating that the wave length of the Poincare mode becomes increasingly short with increasing friction. The damping coefficient gradually increases with increasing friction over the high frequency region, but the trend is reversed over the low frequency region. In case of Kelvin wave the present study substantiates the characters of Kelvin wave examined by Mofjeld (1980) and Lee (1988). Based on the examination of frictional effects on the tidal wave propagation, the co-oscillating tides in the Yellow Sea are examined by considering both the head opening and bottom friction effects. As friction is introduced and increased in addition to partial opening at bay head, the location of the amphidromic point near the Shantung Peninsula moves more southwestward. This southwestward movement of the amphidromic point is increasingly compatible with the observed location of Ogura's or Nishida's tidal chart of the M$_2$ tide.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.241-248
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• 2004

In general, the salient features if the floating breakwater have excellent regulation of sea-water keeping the marine a1ways clean, up and dorm 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 catenary. Numerical method is based at the Green function method and eigenfunction expansion method. The validity of the present is confirmed by comparing it with the result of Ijima et a1.(1975) fer tensile maxed floating breakwater. According to the numerical results, drift and width of the floating breakwater affect at the wave transformation greatly, and incident wave of long period is well transmitted to the rear of the floating breakwater.

• 수산해양기술연구
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• 제15권1호
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• pp.35-42
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• 1979

This paper concerns the receding of the eastern coastline of Korean peninsula at a macroscopic point of view, the result is as following. 1. Eastern coast is gradually developed from maturity stage to full maturity stage. 2. The coastline recession due to sea level rise is amounted to the receding distance, x=0.045 m per yr. 3. The author proposes another classification from the new view point, which is classified by comparing quantities between river supplying sediment loads, and the littoral drifting due to wave actions. According this, eastern coast is receding(Type Q-A), and we could find it's geomorphological characteristics. 4. The general piofile of eastern coast sand beach is erosional storm profile(Type I) which accompany offshore bar. 5. From the wave measuring data of eastern coast(Hoopo port), I can derive the linear regression line of the exceedance probability of wave height from the log-normal distribution. $z=O. 113+4.335 log_lo H, r=0.983.$ Above equation made it possible to estimate $\omega[=P(H>H_c)]for the effective wave height H_c=2. Om4, 4. Om and their corresponding values are considerable (7.8%, 0.3%) 6. Eastern coastline certainly have the tendency of erosive and receding, owing to the sea level rise, poor sediment source and effective wave actions. It's very desirable to survey coastline evolution for a long time systematically, in order to make more elaborate diagnosis.

• 한국해양환경ㆍ에너지학회지
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• 제1권2호
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• pp.71-81
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• 1998

이 논문에서는 홍도와 마라도에서의 파랑의 통계적 특성을 살펴보았다. 두 지역에서의 스펙트럼법과 시계열에서 얻은 유의파고를 이용하여 파고주기결합분포를 얻었으며 여러 가지 통계적인 특성을 살펴보았다. 주파수의 대역폭이 협대역이 아닌 경우에 개별 파고분포에 롱기히긴스가 제안한 수정레일리분포를 사용할 수 있다. 그러나 이 분포함수는 경험상수를 결정해야하는 불편함 때문에 널리 사용되지 않고 있었다. 본 논문에서는 수정레일리분포의 경험상수를 결정하는 간단한 방법을 제안하였다. 설계파고의 추정에서 서로 다른 분포함수 선택에 따른 영향은 크지 않다. 그러나 스펙트럼법과 시계열에서 얻은 파랑자료 사용에 따라서 한계파고의 추정치는 큰 차이를 보인다.

• Ocean Systems Engineering
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• 제10권1호
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• pp.25-47
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• 2020

A study of the wave conditions for the Asabo offshore location at the Qua Iboe oil field in Eastern Nigeria has been carried out. Statistical analysis was applied to three (3) years of data comprising spectral periods, Tp and significant wave heights, H_s. The data was divided into two (2); data from October to April represents one set of data and data from May to September represents another set of data. The results were compared with similar studies at other locations offshore of West Africa. It was found that there is an absence of direct swellwaves from the Southern Ocean reaching the location under study (the Asabo site). This work suggests that the wave system is largely emanating from the North Atlantic storms. The presence of numerous islands near the Asabo location shields the site from effects of storms from south west and therefore swells from the Southern Ocean. It is noted that the local wind has little or no contribution. An H_s maximum of 2 m is noted at the Asabo offshore location. It is found that the Weibull distribution best describes the wave distribution at Asabo. Thus, the Weibull distribution is suggested to be adequate for long term prediction of extreme waves needed for offshore design and operations at this location.