• 한국해양학회지
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• v.29 no.2
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• pp.83-94
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• 1994

Two-dimensional tidal and tidal residual currents in Chinhae Bay are investigated by field observations, hydraulic and numerical experiments. The results of hydraulic and numerical model experiments roughly coincide with the field measurements. Maximum tidal currents during the spring and neap tides in Kaduk and Kyunnaeryang channel and the central channel of Chinhae Bay are strong as 90 to 110 and 30 to 40 cm/s respectively, and strong tidal residual currents having numerous eddies take place. Maximum tidal currents during the spring and neap tides in the western and northern parts of the bay are weak as below 30 and 10 cm/s respectively, and also tidal residual currents are relatively weak. Tidal residual currents in the northern part of Kajo-do go toward the north, whereas the currents in the southern part move down the bay, and the currents rotating clockwise occur around Bu-do. The surface currents in the bay depend strongly on the wind and river inflow, and such phenomena are more remarkable during he neap tide than the spring tide.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.167-181
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• 2010

To predict changes in the marine environment of the Beolgyo Stream Estuary in Jeonnam Province, South Korea, where cohesive tidal flats cover a broad area and a large bridge is under construction, this study conducted numerical simulations involving tidal flow and cohesive sediment transport. A wetting and drying (WAD) technique for tidal flats from the Princeton Ocean Model (POM) was applied to a large-scale-grid hydrodynamic module capable of evaluating the flow resistance of structures. Derivation of the eddy viscosity coefficient for wakes created by structures was accomplished through the explicit use of shear velocity and Chezy's average velocity. Furthermore, various field observations, including of tide, tidal flow, suspended sediment concentrations, bottom sediments, and water depth, were performed to verify the model and obtain input data for it. In particular, geologic parameters related to the evaluation of settling velocity and critical shear stresses for erosion and deposition were observed, and numerical tests for the representation of suspended sediment concentrations were performed to determine proper values for the empirical coefficients in the sediment transport module. According to the simulation results, the velocity variation was particularly prominent around the piers in the tidal channel. Erosion occurred mainly along the tidal channels near the piers, where bridge structures reduced the flow cross section, creating strong flow. In contrast, in the rear area of the structure, where the flow was relatively weak due to the formation of eddies, deposition and moderated erosion were predicted. In estuaries and coastal waters, changes in the flow environment caused by artificial structures can produce changes in the sedimentary environment, which in turn can affect the local marine ecosystem. The numerical model proposed in this study will enable systematic prediction of changes to flow and sedimentary environments caused by the construction of artificial structures.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.41-51
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• 2013

The tidal creek dependent mass transport characteristic in Gyeong-Gi Bay (west coast of Korea) was studied using field measured data and numerical model. Gyeong-Gi Bay consists of 3 main tidal channels and contains a well-developed vast tidal flat. This region is famous for its large tidal difference and strong current. We aim to study the effect of tidal creek in the tidal flat on the mass exchange between the estuary and the ocean. For numerical application, the application of unstructured grid feature is essential, since the tidal creek has complicated shape and form. For this purpose, the FVCOM is applied to the study area and simulation is performed for 2 different cases. In case A, geographic characteristics of the tidal creek is ignored in the numerical grid and in case B, the tidal creek are constructed using unstructured grid. And these 2 cases are compared with the field measured cross-channel mass transport data. The cross-channel mass transport at the Yeomha waterway mouth and Incheon harbor was measured in June, 9~10 (Spring tide) and 17~18 (Neap tide), 2009. CTD casting and ADCP cross-channel transect was conducted 13 times in one tidal cycle. The observation data analysis results showed that mass transport has characteristic of the ebb dominance Line 1 (Yeomha waterway mouth), on the other hand, a flood dominant characteristic is shown in Line 2 (Incheon harbor front). By comparing the numerical model (case A & B) with observation data, we found that the case B results show much better agreement with measurement data than case A. It is showed that the geographic feature of tidal creek should be considered in grid design of numerical model in order to understand the mass transport characteristics over large tidal flat area.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.1
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• pp.56-60
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• 2001

Tidal asymmetry which is generated at the mouth of an estuary tends to be more serious toward the upper stream due to the growth of shallow tides. Thus careful observations and applications for the shallow tides are needed if studies related to sediment or pollutant transport are carried on. An aim of the present study was to clarify the characteristics of generation and propagation of shallow tides by various numerical experiments including the effect of inter-tidal zone. The results of the present study will give a fundamental guide for the analysis of tidal envirorunental changes and for the design of a numerical model if coastal constructions are conducted.

• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.421-432
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• 2007

To investigate temporal and spatial variations of hydrodynamics and environmental conditions in Gyeonggi Bay, including Han River estuary, numerical experiments were performed using 3-dimensional fine grid numerical ocean model. The model successfully reproduced the physical phenomena already known in Gyeonggi Bay where tide and fresh water discharge are dominant forcings. The calculated harmonic constants of tide and tidal current agreed well with those of observations at nine tide stations and two tidal current stations. Tidal asymmetries along the Yeomha Waterway, mainly caused by non-linear effect, were well reproduced and agreed well with observations. Time series of salinity at four stations(A, B, C and D) and horizontal distributions of monthly averaged salinity show that Gyodong and Seokmo Waterways play an important role in fresh water discharge into the Gyeonggi Bay rather than Yeomha Waterway.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.1
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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.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.2
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• pp.176-197
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• 1995

Two-dimensional and three-dimensional structures of tidal currents on southeastern waters of Korea off Kyungnam coast were investigated via a series of numerical models based on dynamic principles. With a two-dimensional tidal model, tidal regimes of major eight tidal constituents (M$_2$, S$_2$, K$_1$, O$_1$, N$_2$, K$_2$, P$_1$, Q$_1$) were computed. Model results showed that the computed results were in good agreement with coastal observations. On the basis of these results the model was further improved to compute three-dimensional structure of tidal current in inner Jinhai and Masan Bay regions of the model area where severe pollutions occur due to red tide by combination of the previous two-dimensional model and inner three-dimensional model. For this work, three-dimensional Galerkin-Spectral model and two-dimensional depth-integrated model are dynamically combined by the method presented by Davies (1980). In addition to the previous work by Davies, the advective term and quadratic bottom friction term are included in present Three-dimensional numerical model. The computed results of M$_2$ tidal current ellipses with respect to depth showed general agreements with those of current observations by KORDI (1990).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.129-135
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• 1990

A two-dimensional nonlinear tidal model of the Asan Bay has been formulated to examine the tide and related hydraulic phenomena. The $M_2$ tidal regime was first computed using the model and the model also was to derive the maximum bed stress and transport potential in the region. Preliminary assessment of relation between sediment transport and the maximum bed stress distribution determined from the model are described.

• Computers and Concrete
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• v.34 no.2
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• pp.169-178
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• 2024

To circumvent the constraints of time-consuming experimental methods, numerical simulation can be one of the most effective approaches to investigating chloride diffusion behaviors in concrete. However, except for the effect of the external environments, the transport direction of the chloride cannot be neglected when the concrete is exposed to the marine tidal zone, especially in certain areas of concrete members. In this study, based on Fick's second law, considering the effects of timevarying, chloride binding capacity, concrete stress state, ambient temperature, and relative humidity on chloride diffusion coefficient, the modified one-dimensional, two-dimensional, and three-dimensional novel modified chloride diffusion theoretical models were established through defining the current boundary conditions. The simulated results based on the novel modified multi-dimensional model were compared with the experimental results obtained from some previous pieces of literature. The comparing results showed that the modified multi-dimensional model was well-fitted with experimental data, confirming the high accuracy of the novel modified model. The experimental results in literature showed that the chloride diffusion in the corner area of the concrete structure cannot be simulated by a simple one-dimensional diffusion model, where it is necessary to select a suitable multi-dimensional chloride diffusion model for simulation calculation. Therefore, the novel modified multi-dimensional model established in this study has a stronger applicability for practical engineering.

• Water for future
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• v.20 no.2
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• pp.161-168
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• 1987

The prediction of changes in the tidal regime due to the construction of a barrier in the Keum River was performed via one-dimensional numerical model. It is shown that a barrier in Mangwolri will lead to a small increase in the $ tidal range. The validity of this prediction is examined using the hydrodynamic analogy with AC circuit theory. Some of preliminary results are presented and discussed.