• 한국해양공학회지
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• 제26권4호
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• pp.37-41
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• 2012

Due to global warming, the need to secure alternative resources has become more important nationally. Because of the very strong current on the west coast, with a tidal range of up to 10 m, there are many suitable sites for the application of TCP (tidal current power) in Korea. In the southwest region, a strong current is created in the narrow channels between the numerous islands. A rotor is an essential component that can convert tidal current energy into rotational energy to generate electricity. The design optimization of a rotor is very important to maximize the power production. The performance of a rotor can be determined using various parameters, including the number of blades, shape, sectional size, diameter, etc. There are many offshore jetties and piers with high current velocities. Thus, a VAT (vertical axis turbine) system, which can generate power regardless of flow direction changes, could be effectively applied to cylindrical structures. A VAT system could give an advantage to a caisson-type breakwater because it allows water to circulate well. This paper introduces a multi-layer vertical axis tidal current power system. A Savonius turbine was designed, and a performance analysis was carried out using CFD. A physical model was also demonstrated in CWC, and the results are compared with CFD.

• 한국지역지리학회지
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• 제8권4호
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• pp.451-467
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• 2002

영산강은 남한의 주요 강에 속하며, 유역은 식량생산의 핵심지 중의 하나이다. 영산강유역에는 범람원과 구릉지가 널리 발달되어 있으며, 현재의 영산호 일대에는 간석지도 넓게 분포했었다. 범람원은 '들'로 불리우며, 골짜기가 중은 '물목'의 상류쪽에 넓게 펼쳐진다. 범람원은 조선 발까지는 거의 전부 논으로 재발되었다. 이 농경지를 배경으로 도회지들이 성장했다. 구릉지는 '등', '까끔', '야산' 등으로 불리우며, 나주시와 영암군에 넓게 분포한다. 구릉지의 농경지개발은 1960년대부터 시작되었으며 오늘날에도 진행되고 있다. 많은 개간지의 영농은 외지인들에 의한 임차농의 형태로 영위된다. 간석지 즉 '뻘밭'은 영산강 하류의 남해만에 넓게 펼쳐져 있었으며, 곳곳에 '개옹'으로 불리우던 갯골이 발달했었다. 간석지는 1981년에 영산강하구둑이 준공된 이후 대대적인 간척사업에 의해 농경지로 개발되어 '영산평야'로 바뀌었다. 새로운 평야의 등장으로 모든 취락이 순수 농촌으로 탈바꿈하였다.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.205-210
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• 2018

To assess the environmental factors determining the zonation between Phacelurus latifolius and Phragmites australis, vegetation survey and soil analysis were performed at a tidal marsh. The vegetation of the tidal marsh was classified into P. latifolius and Suaeda japonica dominated quadrats, P. latifolius and P. australis dominated quadrats, P. australis dominated quadrats, and P. australis and other land plants dominated quadrats. The density of P. latifolius ($83.7{\pm}5.5\;shoots\;m^{-2}$) was higher than that of P. australis ($79.3{\pm}12.1\;shoots\;m^{-2}$) in each dominated quadrat but height of two species were similar. Soil environmental characteristics of P. latifolius dominated quadrats appeared to be affected by tide based on higher soil electric conductivity ($EC_{PL}=1530{\pm}152{\mu}Scm^{-1}$ ; $EC_{PA+PL}=689{\pm}578{\mu}Scm^{-1}$ ; $EC_{PA}=689{\pm}578{\mu}Scm^{-1$) and lower pH ($pH_{PL}=5.96{\pm}0.16$ ; $pH_{PA+PL}=6.28{\pm}0.31$ ; $pH_{PA}=6.38{\pm}0.22$). In redundancy analysis, environmental characteristics of P. latifolius dominated quadrats and P. australis dominated quadrats were clearly separated and those of P. latifolius and P. australis co-dominated quadrats were similar to P. australis dominated quadrats. From our investigation, P. latifolius showed relatively high competitiveness when compared to P. australis in lower tidal zone rather than upper tidal zone. Zonation of P. latifolius and P. australis seems to be a transitional zone between halophytes and land plant species.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.519-519
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• 2023

Estuarine dams are a recent and global phenomenon. While estuarine dams can provide the benefit of improved freshwater resources, they can also alter estuarine processes. Due to the wide range of estuarine types and estuarine dam configurations, the effect of estuarine dams on estuaries is not well understood in general. To develop a systematic understanding of the effect of estuarine dam location and freshwater discharge interval on a range of estuarine types (strongly stratified, partially mixed, periodically stratified, and well-mixed), this study used a coupled hydrodynamic-sediment dynamic numerical model (COAWST) and compared flow, sediment transport, and morphological conditions in the pre- and post-dam estuaries. For each estuarine type, scenarios with dam locations at 20, 55 and 90 km from the mouth and discharge intervals of a discharge every 0.5, 3, and 7 days were investigated. The results were analyzed in terms of change in tide, river discharge, estuarine classification, and sediment flux mechanism. The estuarine dam location primarily affected the tide-dominated estuaries, and the resonance length was an important length scale affecting the tidal currents and Stokes return flow. When the location was less than the resonance length, the tidal currents and Stokes return flow were most reduced due to the loss of tidal prism, the dead-end channel, and the shift from mixed to standing tides. The discharge interval primarily affected the river-dominated estuaries, and the tidal cycle period was an important time scale. When the interval was greater than the tidal cycle period, notable seaward discharge pulses and freshwater fronts occurred. Dams located near the mouth with large discharge interval differed the most from their pre-dam condition based on the estuarine classification. Greater discharge intervals, associated with large discharge magnitudes, resulted in scour and seaward sediment flux in the river-dominated estuaries, and the dam located near the resonance length resulted in the greatest landward tidal pumping sediment flux and deposition in the tide-dominated estuaries.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2018년도 공동국제학술발표회
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• pp.45-45
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• 2018

• 한국항해항만학회지
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• 제32권4호
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• pp.305-313
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• 2008

Recently it was known that the problems of nearshore processes and damage of berth and counter facilities frequently had appeared at the small fishery port, such as Daebang near Samcheonpo city, Korea. Here we try to analyze the impact of the rearrangement of counter facilities and berth layout adopted for tranquility of its inner harbor. Because this harbor is being connected to Daebang channel, the rearrangement of the structures might affect to the current speed and direction and wave height, so do to the sea bottom undulation. Therefore, we made model test for the several layouts of the berth and breakwater in this area. Numerical model result shows that the bottom was eroded by 1m by tidal currents and the speed of flow did not shrink, even after the construction work was completed. The direction of the sand movement was downdrift. Although the model study gave reasonable description of beach processes and approach channel sedimentation mechanism, it is necessary to compare with the field history, including the records of waves, tides and bottom materials, etc. for better prediction.

• Ocean and Polar Research
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• 제32권2호
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• pp.123-135
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• 2010

Around Tongyeong coasts which located in southern coast of Korea composed to the complex coastal line and scattered by small islands. It also has been distributed to a complicated bathymetric structure by several types of channels. This study carried to analyze the spatial characteristics of macrobenthic community and benthic environmental variance on sub-tidal area based on multivariate statistics tools. Sediment composition varied from muddy sand to mud, and along the channels, it composed to a heterogeneous bottoms mixed by shell fragment, cobbles and mud. Organic contents on the surface sediment varied 1.1-3.9%. Total of 272 species, $33,349\;ind./m^2$ of macrobenthos identified in all of sample area. Polychaetes also prevailed among the specimen. L. longifolia, P. pinnata dominated based on density. Considering on the biomass, echinoderm S. lacunosa, A. tricoides listed. Closer to the coastal area, the density and diversity were higher. Community structure based on cluster analysis was discriminated into three groups. Each group was also characterized by geographical state such as depth, sediment composition. In addition, when applied to the bathymetric data, the channel, which composed to the mixed sediment, made a role of limited factor which characterized to benthic community. Because the specimen around the channel have been affected on the diverse sediment mixture. Most of benthic studies in the southern coast of Korea focused to the condition of benthic organic pollution spatially, because along the coast, it also developed a aquaculture ground and industrial complex. But, as results, most of the area, it turn out the less polluted areas nevertheless similar environment situation. It supposed that benthic community affect to the bottom sediment composition by physical characteristics.

• Ocean and Polar Research
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• 제36권1호
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• pp.1-12
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• 2014

This study investigates spatial and temporal variations in the generation and propagation of internal tides around the Korea Strait using a three-dimensional high resolution model (Regional Ocean Modeling System; ROMS). The model results were verified through comparison with in-situ current measurements from an array of 12 acoustic Doppler current profilers (ADCPs) deployed in the Korea Strait. Fluxes and distributions of internal tidal energy were calculated using simulation results gathered in February and August. Our analyses reveal that energetic semidiurnal internal tides are generated in a region around the Korea Strait shelf break ($35.5^{\circ}N$, $130^{\circ}{\sim}130.5^{\circ}E$), where the strong cross-slope semidiurnal barotropic tidal currents interact with a sudden topographical change. The semidiurnal internal tidal energy generated in summer displays values about twice as large as values in winter. Propagation of semidiurnal internal tides also reveals seasonal variability. In February, most of the semidiurnal internal tides propagate only into the open basin of the East Sea due to weak stratification in the Korea Strait, which inhibits their southwestward propagation. In August, they propagate southwestward to $35.2^{\circ}N$ along the western channel of the Korea Strait because of strong stratification. In addition, semidiurnal internal tides generated in a region west of Tsushima Island are found to propagate to the coast of Busan. This can be explained by the intensified stratification due to the strong intrusion of bottom cold water in the western channel of the Korea Strait during summer.

• 한국해양학회지
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• 제13권1호
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• pp.29-34
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• 1978

인천항 부근해역은 우리나라 연안에서 가장 조차가 큰 천해역으로서 연안 및 섬주위로 간석지가 매우 잘 발달되어 있다. 따라서 동 해역은 오래전부터 큰 조차를 이용한 조력발전 후보지로 인정되어 왔고 앞으로의 개발전망이 밝을 뿐 아니라 광대한 간석지를 개발하기 위한 간척사업 후보지로 각광을 받고 있다. 이와 같은 개발계획의 대상으로 인정되는 해역에 있어서의 조류에 대한 정확한 조사연구는 중요한 일이라 생각된다. 인천항 부근해역의 조류에 관해서는 이(1963), 강(1972) 및 이(1972)등의 조사보고가 있는데 이들 조사관측 및 국내에서 실시되어 온 일반적인 조류관측은 거의 대부분이 동시관측에 의한 것이 아닐뿐더러 각 조기별 즉, 대조, 중조, 소조,기별로 실시된 것이 아니므로 각 조기별로 또한 각 지역별로 동시에 나타나는 조류의 특성을 비교하는 데에는 문제점이 있었다 하겠다. 우리나라 남해안이나 특히 서해안과 같이 조석이 큰 해역에서는 각 조기별로 조류의 특성이 매우 다르기 때문에 이를 비교파악 하기 위한 여러 지점에서의 조기별 동시 조류관측은 매우 어렵지만 의미있는 일이라 생각된다. 본조사에 있어서는 특히 이러한 점을 최대한으로 고려하여 실시되었다.

• 한국산학기술학회논문지
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• 제22권4호
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• pp.601-610
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• 2021

해안구조물 설치 전, 후의 금강하구역 해수유동 양상을 CASE별로 비교하기 위해서 수심적분된 그리고 조간대 처리기법이 적용된 해수유동 수치모형인 FLOW2DH를 사용하였다. 실험조건은 해안구조물 설치 전(CASE1), 해안구조물 설치 후(CASE2), 배수갑문운영 추가(CASE1Q, CASE2Q) 및 현재 상태(CASE3)로 구성된다. CASE1의 경우, 자연형 하구의 안정화된 해수유동 양상을 보여주고 있고, CASE2의 경우, 설치된 해안구조물들로 인하여 금강하구역의 유속 및 유향에 변화가 발생하였다. 특히, CASE2의 개야수로 구간(P5~P9)은 CASE1과 대비하여 유속이 10~30% 크게 계산되었다. 금강하굿둑과 가장 가까운 군산 내항(P4)의 경우는, CASE1Q와 CASE2Q의 낙조 시 2.7시간의 배수갑문의 방류로 인하여 낙조 유속이 다른 CASE들과 비교하여 약 250~300% 빨라졌다. 이는 퇴적물이동에 영향을 줄 것이고, 나아가 해저지형변화를 야기할 것으로 예측된다. 현재 상태인 CASE3의 경우, 금강하구와 주변 해안역의 유속과 유향을 검토한 결과 안정화 단계로 접어들고 있는 것으로 판단된다.