• 물과 미래
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• 제24권4호
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• pp.41-48
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• 1991

본 연구는 2차원비선형 동수역학방정식을 이용하여 가막만의 조류의 특성을 해석하였다. 사용된 기초방정식은 Navier-Stokes의 운동 및 연속방정식이 이용되었고, 방정식을 구성하는 각항의 특성에 관해 상세하게 살펴본 후, 그것을 음적차분법을 사용하여 수치해석하였다. 수치모델은 2차원 단층모델로 구성하였으며, 수립된 수치모델을 가막만에 적용하여, 해의 안정성과 수렴성을 검토하였으며, 모델의 결과와 현지의 관측치를 비교하여 수치모델의 재현성을 검토하였다. 본 수치실험결과 다음의 것들이 증명되었다. I) 실측치와 비교해서 조류의 유향, 유속에 대해서 재현성은 양호하게 나타났으며, II) 안정해를 얻기위한 조석주기는 4주기었다. 또한, III) 조도계수는 C=(1/n)$h^{1/6}$으로 충분히 나타낼수 있었다.

• 해양환경안전학회지
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• 제5권1호
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• pp.9-18
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• 1999

To predict the oil spill dispersion phenomena in the ocean, the oil spill response model, which can be used for strategic purpose on the oil spill site, based on Lagrangian particle-tracking method was formulated and applied to the neighboring area with Pusan port where the oil spill incident occurred when the tanker ship No.1 Youil struck on a small rock near the Namhyungjeto on September 21, 1995. The real-time tidal currents to be required as input data of the oil spill model were obtained by the two-dimensional hydrodynamic model and the tide prediction model. Evaluation of tidal currents using observation data was successful. For wind data, other input data of oil spill model, observed data on the spot were used. To verify the oil spill model, the oil spill modelling results were compared with the field data obtained from the spill site. Compared the modelling results with the observation data, there exist some discrepancies but the general pattern of modelling results was similar to that of field observation. The modelling results on 7 days after spill occurred showed that the 40% of spilled oil is in floating, 36% in evaporated, 23% at shore, and 1% in out of boundary, respectively. According to the evaluation of weighting curves of effective components to the dispersion of oil, the winds make a 37% of contribution to the dispersion of oil, turbulent diffusion 39.5%, and tidal currents 23.5%, respectively. Provided the more accurate wind data are supported, more favorable results might be obtained.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.154-159
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• 2001

Nakdong estuary is located at south-eastern coast of the Korea. A lot of sediment from upper river was deposited at this area. It has caused many problems such as changes in topography and tidal current. In this paper, field observation data on tidal currents and sediments were investigated as well as historical topographic changes by dredging and reclamation of the foreshore. Then, the numerical model considered the settling velocity of the suspended solids according to the particle size was applied to examine the characteristic of deposition. The results are as follows : 1. Changes of characteristics of deposition were caused by topographic changes of Nakdong estuary 2. Characteristics of deposition were influenced by river plume and tidal currents. 3. Numerical model which considers settling velocity reappeared distribution of deposition by particle-size. 4. Used model is only resonable for discussion in the quality, so, it is strongly suggested that the new model development is needed including the quatitative deposition processes.

• 한국해양공학회지
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• 제19권1호
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• pp.1-7
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• 2005

Tidal circulation in a closed bay using a variation of bottom roughness was investigated through the numerical experiments based on a finite difference multi-level model. Various distributions of bottom roughness in the bay were implemented to determine their effects. It hadbeen determined that residual currents can be generated from the differences of the bottom roughness between streaming and reverse flow directions. The magnitude of residual currents and volume flow rate increase when the relative ratio of bottom roughness between streaming and reverse flow directions increase. Circulation in the closed bay is also improved by the employment of the change of bottom roughness.

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 2002년도 한국해안해양공학발표논문집 Proceedings of Coastal and Ocean Engineering in Korea
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• pp.208-211
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• 2002

The Kyunggi Bay (125-l28E, 36-38N) is a macro-tidal bay in the western central port of Korean Peninsula(Fig. 1). The Bay characterizes its feature as wide tidal flats, deep tidal channels and tidal sand ridges running in parallel to tidal flows. The macro-tidal range (up to approximately 8.6m) and consequent strong tidal currents erode the bottom sediment and selectively transport to the low-energy area forming tidal ridges or tidal flats. (omitted)

• Ocean and Polar Research
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• 제39권3호
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• pp.169-179
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• 2017

The "GeoDrifter" is a newly-developed surface drifter with high temporal resolution. It is the first time that high-frequency drifters have been deployed in the East/Japan Sea. The purpose of this study is to introduce the phenomena experienced by these drifters flowing along with the Tsushima Current across the East/Japan Sea, focusing on high-frequency variability, and to discuss them in comparison with previous observations. The observed basin-scale circulation of the Tsushima Current generally coincides well with the known schematic circulation. The GeoDrifter trajectories also show inertial oscillations almost everywhere in the oceanic regions of the East/Japan Sea, strong semi-diurnal tidal currents in the western part of Korea Strait, diurnal currents much stronger than semi-diurnal currents in the upstream region of the Nearshore Branch off the Japanese coast, and many warm eddies in the Yamato Basin, all comparable to the observational results reported in the previous studies. An interesting point is that the semi-diurnal tidal currents undergo a great spatial variation in the western part of the Korea Strait. The observed features that cannot be explained are, among others, strong counter-clockwise motions with oscillating period about 51 hours appearing in the upstream region of the Nearshore Branch off the Japanese coast and the different tidal behaviors between upstream and downstream regions of the latter.

• 한국해안해양공학회지
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• 제16권1호
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• pp.47-55
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• 2004

GUI를 이용하여 연안해역에서 항만개발, 방조제 건설, 준설 등의 해상 공사 시 발생하는 부유사(SS)의 이동 및 확산과정을 편리하게 예측할 수 있는 모의시스템(KUSSMOS)을 개발하였다. 모의시스템은 2차원 유한요소모형을 사용하여 해수유동을 모의하고, 입자추적모형을 사용하여 부유사 이송-확산을 모의한다. 군산해역 준설공사에 대해 수립된 시스템을 적용한 결과, 유속과 부유사 농도가 비교적 관측치와 일치하는 양호한 계산결과를 보였다.

• 한국해안해양공학회지
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• 제6권4호
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• pp.335-339
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• 1994

관측치와 모형 계산결과를 이용하여 Tartar 해협에서의 해류를 흐름 규모별로 분석하였으며, 조석현상과 일반적인 순환특성에 주안점을 두었다. 최대조류의 발생지점은 안정된 경계 흐름지역내에 위치함을 할 수 있었다. 다양한 기상조건 하에서의 흐름의 안정성과 소역에서의 에너지 집중은 바닥이 거친 지역에서 발생하는 조류의 비선형 효과로서 설명될 수 있다.

• 에너지공학
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• 제28권1호
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• pp.65-72
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• 2019

한국정부는 재생에너지를 이용한 발전량 비중을 2030년까지 총 발전량의 20%까지 높이겠다는 목표를 제시하였다. 풍부한 해양 신재생에너지 자원은 한국정부가 이 목표를 달성하는데 중요한 역할을 할 수 있을 것이다. 이 논문은 1.0 m/s의 낮은 유속에서도 높은 효율을 달성할 수 있는 유동유발진동 현상을 이용한 조류에너지 발전기술을 소개하고 한국 7개 해안의 평균유속을 바탕으로 높은 효율을 달성할 수 있는 유동유발진동 발전기의 최적 설계를 제안하고자 한다. 또한, 이를 바탕으로 각 해안에서 발전할 수 있는 이론적 잠재량을 산정하고자 한다. 유동유발 발전기술을 이용한 연간 이론적 최대발전량은 221.77 TWh로 예측되었고 이는 2013년 한국의 총 전력소비량의 42.3%에 해당한다. 본 연구결과는 유동유발진동을 이용한 발전기술을 이용한 조류발전기술이 한국 정부가 제시한 목표를 달성하는데 중요한 역할을 할 수 있음을 보여준다.

• Ocean and Polar Research
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• 제33권3호
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• pp.309-319
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• 2011

This is a preliminary study of the feasibility of obtaining reliable tidal current harmonic constants, using one month of current observations, to verify the accuracy of a tidal model. An inference method is commonly used to separate out the tidal harmonic constituents when the available data spans less than a synodic period. In contrast to tidal constituents, studies of the separation of tidal-current harmonics are rare, basically due to a dearth of the long-term observation data needed for such experiments. We conducted concurrent and monthly harmonic analyses for tidal current velocities and heights, using 2 years (2006 and 2007) of current and sea-level records obtained from the Tidal Current Signal Station located in the narrow waterway in front of Incheon Lock, Korea. Firstly, the l-year harmonic analyses showed that, with the exception of $M_2$ and $S_2$ semidiurnal constituents, the major constituents were different for the tidal currents and heights. $K_1$, for instance, was found to be the 4th major tidal constituent but not an important tidal current constituent. Secondly, we examined monthly variation in the amplitudes and phase-lags of the $S_2$ and $K_1$ current-velocity and tide constituents over a 23-month period. The resultant patterns of variation in the amplitudes and phase-lags of the $S_2$ tidal currents and tides were similar, exhibiting a sine curve form with a 6-month period. Similarly, variation in the $K_1$ tidal constant and tidal current-velocity phase lags showed a sine curve pattern with a 6-month period. However, that of the $K_1$ tidal current-velocity amplitude showed a somewhat irregular sine curve pattern. Lastly, we investigated and tested the inference methods available for separating the $K_2$ and $S_2$ current-velocity constituents via monthly harmonic analysis. We compared the effects of reduction in monthly variability in tidal harmonic constants of the $S_2$ current-velocity constituent using three different inference methods and that of Schureman (1976). Specifically, to separate out the two constituents ($S_2$ and $K_2$), we used three different inference parameter (i.e. amplitude ratio and phase-lag diggerence) values derived from the 1-year harmonic analyses of current-velocities and tidal heights at (near) the short-term observation station and from tidal potential (TP), together with Schureman's (1976) inference (SI). Results from these four different methods reveal that TP and SI are satisfactorily applicable where results of long-term harmonic analysis are not available. We also discussed how to further reduce the monthly variability in $S_2$ tidal current-velocity constants.