• Title/Summary/Keyword: Tidal Current Environment

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Interaction of Multi Current Power Generation Blade (멀티 해류발전 블래이드 간섭 연구)

  • Jo, Chul-Hee;Park, Kwan-Kyu;Cho, Won-Chul
    • Journal of the Korean Solar Energy Society
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    • v.26 no.4
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    • pp.47-54
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    • 2006
  • The current power generation is very suitable renewable energy for the application to Korean western and south coastal regions where characterized as having high current speed. Being different from tidal power generation that needs tremendous dam structure to preserve water, the current power generation utilizes the ocean current flow without damaging to estuary area and its environment. There are still many areas to understand the characteristics of current power generation for the actual field installation. As designing muti module with several rotors, the interaction between rotors will occur that would affect the efficiency and RPM of each rotor. In this study, the interactions caused by gaps between rotors in multi module are studied.

Analysis of a Change of Hydrodynamic Environments due to the Port Developments in the Intertidal Zone (조간대 발달영역에서 개발에 따른 유동환경변화 해석)

  • Jung, Jae-Hyun;Lee, Joong-Woo;Jeong, Young-Hwan;Jun, Sung-Hwan;Kim, Kang-Min
    • Journal of Navigation and Port Research
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    • v.31 no.8
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    • pp.689-695
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    • 2007
  • The under developing estuarial port Bupsung is bounded by a river and the sea, and has several well developed tidal lands, where the littoral drift is strong due to the tide and the river discharge. The study area is located at the inner part of a concave bay and has a large tidal range due to the water discharge through the Watan-chun and Junnam-dike. In beginning stage of the ocean physical impact study, the tidal modeling is very important and difficult especially in this area. Moreover, we need a model experiment after the verification of the formulated model based on ocean survey. In this study, we constructed a numerical model to the Bupsung port coastal boundaries, which varies with the past and future development and made simulation with it. The result after development shows that there is a decrease of velocity on flood current and a increase on Ebb current and the minor variation of the tide level, compared with before development.

Three-Dimensional Mixing Characteristics in Seomjin River Estuary (섬진강 하구역의 3차원 혼합특성 연구)

  • Kim, Jong-Kyu;Kwak, Gyeong-Il;Jeong, Jeong-Ho
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.3
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    • pp.164-174
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    • 2008
  • In this study we try to identify the three-dimensional mixing characteristics of Seomjin River discharges in Seomjin River Estuary and Gwangyang Bay using a seasonal field observation (CTD) during spring tide and a three-dimensional numerical model with EFDC (Environmental Fluid Dynamics Code). The tidal elevation conditions of the four main tidal harmonic constituents on the open boundary and river discharges and thermal effluents at the specific boundary are considered. The calculated harmonic constants of tide and tidal current agreed well with those of observations at two stations for tide and two stations for tidal current. The model successfully reproduced well known the estuarine circulation in Seomjin River Estuary where tide and river discharges are dominant forcings. In the winter mean discharges case, tidal currents move Seomjin River discharges in Seomjin River mouth and in the summer mean discharges case, river flows move Seomjin River discharges near ae Seomjin River Estuary. A three-dimensional mixing characteristics of Seomjin River Estuary show well a three-dimensional estuarine circulation and thermal effluents effect to the seasonal variation of river discharges.

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Calculating Average Residence Time Distribution Using a Particle Tracking Model (Particle Tracking Model을 이용한 평균체류시간의 공간분포 계산)

  • Park, Sung-Eun;Hong, Sok-Jin;Lee, Won-Chan
    • Journal of Ocean Engineering and Technology
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    • v.23 no.2
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    • pp.47-52
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    • 2009
  • A Lagrangian particle tracking model coupled with the Princeton Ocean Model were used to estimate the average residence time of coastal water in Masan Bay, Korea. Our interest in quantifying the transport time scales in Masan Bay was stimulated by the search for a mechanistic understanding of this spatial variability, which is consistent with the concept of spatially variable transport time scales. Tidal simulation was calibrated through a comparison with the results of semi-diurnal current and water elevation measured at the tidal stations of Masan, Gadeokdo. In the model simulations, particles were released in eight cases, including slack before ebb, peak ebb, slack before flood, and peak flood, during both spring and neap tides. The averaged values obtained from the particle release simulations were used for the average residence times of the coastal water in Masan Bay. The average residence times for the southeastern parts of Somodo and the Samho River, Masan Bay were estimated to be about 20~50days and 70~80days, respectively. The spatial difference for the average residence time was controlled by the tidal currents and distance from the mouth of the bay. Our results might provide useful for understanding the transport and behavior of coastal water in a bay and might be used to estimate the dissimilative capacity for environmental assessment.

Seasonal Variations of Physical Conditions and Currents in the Sea Near Gadeok-Sudo (가덕수도 근해에서 물리적 현상과 해류의 계절 변동)

  • Jang, Sung-Tae;Jeon, Dong-Chull;Shin, Chang-Woong
    • Ocean and Polar Research
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    • v.30 no.1
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    • pp.33-46
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    • 2008
  • In order to investigate seasonal variations of the physical environments in the region of Jinhae Bay-Nakdongpo, we carried out hydrographic surveys from November 2000 to November 2001. Horizontal and vertical distribution of salinity and temperature shows large seasonal variations. Water column is well mixed in winter and stratified in summer. Low-salinity water is distributed in the form of patches because of the drainage control at the Nakdong River. Seasonal variations in the sea near Gadeok-Sudo are affected by topography, river discharge and tidal current. Currents have been measured using a bottom mounted ADCP and DCM12 between November 2000 and August 2001 in the Gadeok-Sudo. The current in the Gadeok-Sudo shows a distinct two-layer structure with reversed current. Low-pass filtered time series of wind, sea elevation and current are coherent for the period of 1-2 days and are attributed to Ekman-like dynamics. Spatial and temporal circulation pattern shows a slight different. The subtidal current in Jinhae Bay goes northward, however is reversed in the Gadeok-Sudo mouth.

Numerical Study on Sea State Parameters Affecting Rip Current at Haeundae Beach : Wave Period, Height, Direction and Tidal Elevation (수치모의를 통한 해운대 이안류에 대한 해상요소의 영향 연구: 파주기, 파고, 파향, 조위)

  • Choi, Junwoo;Shin, Choong Hun;Yoon, Sung Bum
    • Journal of Korea Water Resources Association
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    • v.46 no.2
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    • pp.205-218
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    • 2013
  • The likelihood of rip current at Haeundae beach according to wave parameters, such as wave height, period, direction, and tidal elevation, was estimated by using numerical simulations with a Boussinesq model, FUNWAVE. To examine the estimation, the rip current occurred on 12th June, 2011 at Haeundae beach was simulated based on observations. For the estimation, the following procedure was carried out. First, extensive numerical simulations of nearshore circulations are performed under various random sea conditions according to the wave parameters. Second, from the numerical results, cross shore components of two-wave-period averaged velocities over the nearshore area were computed, and their seawardly maximum was defined as rip current velocity of the area. Third, using time series of the rip current velocity, we computed the ratio of the simulation time and the time period in which the rip current velocity exceed a threshold velocity for rip-current accidents, and thus the ratio was quantified as the likelihood of rip current at Haeundae beach for the input wave parameters. From the resultant estimations, it was found that the rip current likelihood increases as wave height and period increase, and tidal elevation decreases.

Research of landscape ecological field-trip learning program development for students at BiIn Bay, Seocheon in South Chung-chong coastal environment (비인만의 해안사구를 활용한 경관생태적 현장학습 프로그램 개발)

  • KANG, Tay-Gyoon
    • Journal of The Geomorphological Association of Korea
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    • v.26 no.1
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    • pp.121-131
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    • 2019
  • The coast of BiIn Bay, Seocheon, is the potential site for the field-trip learning program. This article is written in the viewpoint of geographical and environmental education. In this study, it is tried to describe geomorphological landscapes of BiIn Bay Seocheon-gun relating with it's physiognomy, based on the Dasa-ri and Songrim-ri coastal sanddunes and the like. Although landforms like tidal flats and rock cliff constitute prominent landscape features in this area, other features such as beaches, coastal dunes, and coastal plains have various ramifications for human communities. Tidal flats, beaches and coastal dunes are formed by the combined actions of longshore current, tidal flows, waves and winds. To some extent, the erosion of sandy coast has been a global phenomenon. Anthropogenic impacts are involved in the transformation of landform. Most favorable field-trip course of BiIn Bay is from Songrim-ri through Dasa-ri and Shinhap-ri to Maryang-ri. This program about coastal landforms in BiIn Bay will contribute not only for educational meanings but also for satisfying the student' curiosity and interest. Also, this field-trip learning program will be suitable for over 4th grade elementary school students and middle school students.

Concentration Changes of Wastewater Effluent Discharge in the Mixing Bone of Masan Sea Outfall (마산만 해양방류 혼합구역에서의 하수농도 분포 변화)

  • Kang See-Whan;You Seung-Hyup;Kim Sang-Ik;Oh Byung-Cheol;Park Kwang-Soon
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.4 no.2
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    • pp.15-24
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    • 2001
  • The concentration changes of discharged wastewater effluents due to ambient current flows and density stratifications in an outfall mixing zone have been investigated by using the outfall mixing zone analysis of Huang et al.[1996]. This analysis was applied to Masan sea outfall case and the concentration distributions of wastewater effluent discharges were simulated using three month period of current-meter data measured in the outfall site. Hourly concentration distributions of wastewater effluents were averaged for the period of 15 days which covers the flow conditions of the neap and the spring tidal currents in Masan Bay. The results show that the wastewater concentrations in the Masan outfall mixing zone were very low due to the higher dilution rates during the period of strong ambient currents and less density stratifications. The higher concentrations in the mixing zone were found in August because of strong density stratifications with low ambient currents. The mixing zone was extended to the west coast beach area because of major tidal current directions. This result can be used to explain the dynamical reasons for the depositional distribution of the contaminated sediments in Masan sea outfall area.

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Dynamic Analysis of Berthed Mooring by Numerical Method (수치해석 기법을 이용한 안벽계류의 동력학적 고찰)

  • 조철희;김두홍;김병환;나인삼
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.04a
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    • pp.69-75
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    • 2001
  • It is very important to secure the marine vessels during entire loading and off-loading operations. The environment influences on loading conditions. the western coastal area of Korea is characterized as a strong current due to a high tidal range. The tension of mooring lines varies as per the current and wave changing its magnitude during the day. A proper mooring arrangement and design of mooring line should be determined as per environment conditions. In this study, a 50,000 DWT container ship being moored is investigated numerically. The dynamic tension of mooring lines is estimated by MORA (Mooring Response Analysis) software. Environmental conditions of selected offshore terminal site are plugged as input data. The mooring line tensions are obtained for various wave frequencies per wave directions. The results demonstrate the change of tensions of lines and the allowable range of safe conditions in berthed mooring.

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Evaluation of the Behavior of Dredged Materials in Ocean Dumping Area

  • Lee, Seung-Chul;Kim, Kang-Min;Kim, Hyung-Chul;Lee, Joong-Woo
    • Journal of Navigation and Port Research
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    • v.30 no.9
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    • pp.755-762
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    • 2006
  • When we consider to develop a new harbor, the most important factor, we think, is the lowest water depth of waterway and approaching channel for safe navigation of vessel. The existing harbors have been being dredged to meet the international trend of jumbo sized vessels by adopting the new design criteria. As the dredged materials over the expected at the design level were common and there are still lack of land based reclamation area, we have no choice to discharge the dredged materials in open sea area In this study, we analysed the behavior of discharged materials at the dumping area of offshore, which were collected from the dredging work at the waterway in Busan New Port. We measured the tidal currents and analyzed the waters of dumping site after the dumping work. These were used to evaluate the numerical models. Suspended Solids(SS) were introduced to the diffusion model. Because of the characteristic of the dumping site, the speed of initial diffusion and settle down of the discharged materials was so fast. Therefore, we believe that the dumped materials do not cause a significant impact to the marine environment.