• 수산해양기술연구
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• 제55권3호
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• pp.252-263
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• 2019

In order to understand the tidal current and mean flow at the west channel of Yeoja Bay in the South Sea of Korea, numerical model experiments and vorticity analysis were carried out. The currents flow north at flood and south at ebb respectively and have the reversing form in the west channel. Topographical eddies are found in the surroundings of Dunbyong Island in the east of the channel. The flood currents flow from the waters near Naro Islands through the west channel and the coastal waters near Geumo Islands through the east channel. The ebb currents from the Yeoja Bay flow out along the west and the east channels separately. The south of Nang Island have weak flows because the island is located in the rear of main tidal stream. Currents are converged at ebb and diverged at flood in the northwest of Jeokgum Island. Tidal current ellipses show reversing form in the west channel but a kind of rotational form in the east channel. As the results of tide induced mean flows, cyclonic and anticyclonic topographical eddies at the northern tip but eddies with opposite spin at the southern tip are found in the west channel of Yeoja Bay. The topographical eddies around the islands and narrow channels are created from the vorticity formed at the land shore by the friction between tidal currents and the west channel.

• 수산해양기술연구
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• 제57권3호
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• pp.214-227
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• 2021

The distribution of tidal current and tidal induced residual current, topographical eddies and tidal residual circulation in the waters surrounding the Geumo Island-An Island channel were identified through numerical model experiments and vorticity balance analysis. Tidal current flows southwest at flood and northeast at ebb along the channel. The maximum flow velocity was about 100-150 cm/s in neap and spring tide. During the flood current in the neap tide, clockwise small eddies were formed in the waters west of Sobu Island and southwest of Daebu Island, and a more grown eddy was formed in the southern waters of Geumo Island in the spring tide. A small eddy that existed in the western waters of Chosam Island during the ebb in neap tide appeared to be a more grown topographical eddy in the northeastern waters of Chosam Island in spring tide. Tidal ellipses were generally reciprocating and were almost straight in the channel. These topographical eddies are made of vorticity caused by coastal friction when tidal flow passes through the channel. They gradually grow in size as they are transported and accumulated at the end of the channel. When the current becomes stronger, the topographic eddies move, settle, spread to the outer sea and grow as a counterclockwise or clockwise tidal residual circulation depending on the surrounding terrain. In the waters surrounding the channel, there were counterclockwise small tidal residual circulations in the central part of the channel, clockwise from the northeast end of the channel to northwest inner bay of An Island, and clockwise and counterclockwise between Daebu Island and An Island. The circulation flow rate was up to 20-30 cm/s. In the future, it is necessary to conduct an experimental study to understand the growth process of the tidal residual circulation in more detail due to the convergence and divergence of seawater around the channel.

• 수산해양기술연구
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• 제58권2호
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• pp.159-174
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• 2022

Flow prediction was carried out through observational survey and three dimensional multi-layered numerical diagnostic model experiment to clarify the time and spatial structure of tidal current and residual flow dominant in the sea exchange and material circulation of the waters around Geumo Islands in the southern waters of Korea. The horizontal variation of tidal current is so large that it causes asymmetric tidal mixing due to horizontal eddies and the topographical effect creating convergence and dispersion of flow direction and velocity. Due to strong tidal currents flowing northwest-southeast, counterclockwise and clockwise eddies are formed on the left and right sides of the south of Sori Island. These topographical eddies are created by horizontal turbulence and bottom friction causing nonlinear effects. Baroclinic density flows are less than 5 cm/s at coastal area in summer and the entire sea area in winter. The wind driven currents assuming summer and winter seasonal winds are also less than 5 cm/s and the current flow rate is high in winter. Density current in summer and wind driven current in winter have a relatively greater effect on the net residual flows (tidal residual current + density current + density driven current) around Geumo Islands Sea area.

• 수산해양기술연구
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• 제57권1호
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• pp.45-56
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• 2021

In order to understand the tide and current around the sea route of Jinhae and Masan passages, tide measurement and 2D numerical model experiments of tidal current and residual flow were carried out. Tide is composed of 84% of semi-diurnal tide, 11% of diurnal tide and 4% of shallow water tide, respectively. Phase lags of the major components for the tide around the study area have little differences. The flows are reversing on the whole, but have rotational form around Jamdo Island, south of Masan passage in spring tide and Ungdo Island, north of Masan passage in middle and neap tide. Current flows the speed of 50 cm/s in the sea areas near small islands, 5 cm/s in Jinhae harbor, Hangam bay and near Jinhae industrial complex and 20-30 cm/s in Jinhae passage, Budo channel and Masan passage. Tide-induced topographical eddies are formed near small islands, but few eddies exist and the flow rate of less than 5 cm/s tidal residual current formed in Jinhae and Masan passages. The flows in Jinhae and Masan passage give a good condition for a passage into Jinhae and Masan harbor.

• 해양환경안전학회지
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• 제24권2호
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• pp.179-187
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• 2018

수치모델실험을 사용하여 한국 서남해 압해도 주변 해역의 조류 및 조석잔차류 분포를 파악하였다. 조류는 대체로 반 일주조가 탁월하며, 조류 주방향은 압해도 주변 다도해역이 좁은 협수로인 관계로 대부분 수로를 따라 형성되었다. 조류타원 형태는 주변수심 및 인근에 산재한 섬 주위 해저지형의 영향으로 대부분 직선에 가까운 왕복성이었으나, 매화도~증도 사이 기점도, 화도, 당사도 주위에 약한 회전성 조류타원 형태였다. 창조류는 화원반도 서쪽 연안을 따라 팔금도~암태도, 암태도~증도 수로에서 북동류한 조류와 함께 압해도 북서쪽 다도해로 빠지고, 낙조류는 반대로 북서 다도해의 협수로를 따라 암태도~증도, 암태도~팔금도를 통과하고 암태도~증도에서의 조류는 팔금도~화원반도 서쪽 연안을 따라 남류했다. 압해도 연안은 창조시 북류한 흐름이 해안에서 동서로 분류되어 압해도 서쪽과 동쪽을 따라 흐르고 낙조시는 조간대 만곡부에서 남류한 흐름과 섬 서쪽과 동쪽에서 남~남동류한 흐름이 팔금도~화원반도 사이로 흘렀다. 조류유속이 강한 곳은 암태도~압해도 사이 합류역이었다. 조석잔차류는 다도해 협수로의 빠른 유속으로 섬 주변 흐름 하류역에 후류와 또는 지형성와류가 형성되었다. 압해도 서쪽에 약한 반시계방향 와류와 압해도 북서 만곡부에 시계방향 환류가 존재했다. 북쪽 협수로를 제외한 압해도 연안은 조간대가 발달되어 조석잔차류 유속이 미약하였다.

• 해양환경안전학회지
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• 제25권5호
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• pp.589-600
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• 2019

한국 남해안 금호열도 주변 다도해역의 조류특성과 해수순환 구조를 파악하기 위해 대조와 소조시 ADCP bottom tracking을 이용한 25시간 선박 항주관측을 실시하였다. 대조시 낙조와 창조 방향은 남동-북서이며, 최강유속은 표층 약 40 cm/s이다. 개도주변은 지형적 특성으로 주변해역의 탁월유향과 다르고, 유향 유속의 분산이 크다. 전 구간 표~저층 흐름에 두드러진 경압모드 성분은 없었다. 이는 좁은 수로와 얕은 수심, 빠른 유속으로 지형성와류나 eddy로 인한 연직혼합이 활발했음을 나타낸다. 소조시 조류는 남남동-북북서, 평균유속은 대조의 85 %이다. 탁월유향은 대조보다 우세하지 못하고 지속시간도 짧다. 흐름은 연직방향 유속시어, 수평와류, 비대칭 조류혼합으로 물질의 수평 연직이동이 왕성할 것으로 추정된다. 일평균조류는 개도 서~북서 수로해역이 북서~북동, 금오도 서쪽은 서남서~남남서 방향 최대 21 cm/s의 흐름이 존재한다. 소리도 서쪽에는 좌선환류나 와류가 형성되었다.