• Proceedings of the Korea Water Resources Association Conference
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• 1996.05a
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• pp.683-688
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• 1996

The purpose of this study is to find seasonal variation of the water circulation in the Chenbuk coastal sea region. Chenbuk coastal sea is investigated with use of a robust diagnostic numerical model. Water circulations in four seasons are calculated diagnostically from the observed water temperature and salinity data and wind data from Kunsan mereorologcal station.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.4
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• pp.360-369
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• 1997

We calculated the residual current forced by buoyancy, wind stress, and tidal stress in the Chinhae Bay using a three-dimensional diagnostic model. The calculated current was also compared with the observation. The flow directs outward from the central area of the Bay in the upper layer, and also forms eddy-shape stucture in the upper and middle layers. The flow of bottom layer shows an opposite pattern compared to those of top and middle layers. The maximum speed was 6.05 em/see (September) and 3.49 cm/sec (November) in the upper layer, and 4.39 cm/sec on both month in the middle layer. The Kinetic energy of November (8.39xlO' W) was larger than that of September (1.24xlO 'W), mainly resulting from larger buoyancy effect in September. In spite of the roughness of the grid size(1 km) and wind date, the calculated flow shows eorrelation(r=0.71) with the observation. We expect that the correlation be increased by increased by adopting the fine grid and the variable coefficients of diffusion and viscosity.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.2
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• pp.204-214
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• 1996

The purpose of this study is to find a variation in traveling patterns of soil and soil diffusion due to construction of the sea dike in Saemangum coastal sea region. Water circulations are calculated diagnostically from the observed water temperature, salinity and wind data, and tidal residual current. Three-dimensional movements of injected particles due to currents, turbulence and sinking velocity are tracked by the Euler-Lagrangian method. Calculated a variation in traveling patterns of soil and soil diffusion due to construction of the sea dike deposited mostly from estuarine area of the Geum River to Gokunsan coastal sea region. This results are believed to be the combined effect of coastal circulation.

• Tribology and Lubricants
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• v.13 no.2
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• pp.74-81
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• 1997

The purpose of this study is to develop a cold rolling oil with lubricity and mill cleanness property under the rolling conditions of high reduction ratio and high rolling speed. Six kinds of oil samples were blended. Evaluation of lubricity and anti-seizuro property of the samples were carried out with a laboratory scale rolling mill, where the contact conditions between work roll and strip are very close to actual cold rolling mill. Laboratory evaluation for dispersion, contamination, anti-oil stain property and residual carbon, etc. were carried out with several testers such as longterm circulation tester, Coulter counter and Conradson tester. A new high speed cold rolling oil with good lubricity and mill cleanness property was developed compared with the previously developed rolling oil.

• Ocean Science Journal
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• v.42 no.3
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• pp.153-163
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• 2007

This study is based on a series of numerical modeling experiments to understand the tidal circulation in the Kangjin Bay (KB). The tidal circulation in the KB is mostly controlled by the inflow from two channels, Noryang and Daebang which introduce the open ocean water into the northern part of the KB with relatively strong tidal current, while in the southern part of the KB, shallowest region of the entire study area, weak tidal current prevails. The model prediction of the sea level agrees with observed records at skill scores exceeding 90 % in terms of the four major tidal constituents (M2, S2, K1, O1). However, the skill scores for the tidal current show relatively lower values of 87, 99, 59, 23 for the semi-major axes of the constituents, respectively. The tidal ellipse parameters in the KB are such that the semi-major axes of the ellipse for M2 range from 1.7 to 38.5 cm/s and those for S2 range from 0.5 to 14.4 cm/s. The orientations of the major-axes show parallel with the local isobath. The eccentricity values at various grid points of ellipses for M2 and S2 are very low with 0.2 and 0.06 on the average, respectively illustrating that the tidal current in the KB is strongly rectilinear. The magnitude of the tidal residual current speed in the KB is on the order of a few cm/s and its distribution pattern is very complex. One of the most prominent features is found to be the counter-clockwise eddy recirculation cell at the mouth of the Daebang Channel.

• Journal of the Korean Geotechnical Society
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• v.35 no.10
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• pp.5-15
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• 2019

In this study, to investigate the effect of long-term performance of energy pile on ground temperature, a numerical analysis was conducted by simulating the ground where an energy pile was installed. In the analysis, a changing distance from the outer perimeter of a heat circulation pipe to the surface of concrete pile for an intermittent operation (8-hour operation, 16-hour stop) was considered. Simulation results showed that long-term heat exchange under the intermittent operation of energy pile reduced a thermal recovery in the ground and increased the ground temperature through the residual thermal energy. In addition, the ground temperature became higher as it got closer to the energy pile and increased as the distance from the outer perimeter of heat circulation pipe to the surface of concrete pile decreased.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.91-97
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• 2021

Background In postaxial polysyndactyly of the foot, the choice of which toe to excise is controversial. It is often treated by resection of the fifth toe to save the lateral neurovascular bundles of the sixth toe. However, the sixth toe is often short and laterally deviated, which may require wedge osteotomy, potentially shortening the phalanx and compromising circulation. This study outlines an individualized method to spare the length and axis of the fifth toe in polysyndactyly with a short and deviated sixth toe. Methods We retrospectively analyzed 38 patients who underwent surgery between 2006 and 2019. The fifth toe was spared in 18 cases, and the sixth toe in 20 cases. The ratios of the forefoot width, angle difference, and toe length were compared between the affected and unaffected sides postoperatively. Complications and subjective judgments on cosmetic results were recorded and compared. Results No significant between-group differences were observed for sex, age at surgery, or the follow-up period. The forefoot width ratio did not significantly differ between the groups. However, the angle difference and toe length ratios showed significantly better results in the fifth toe-spared group than in the sixth toe-spared group (P<0.05 and P<0.01, respectively). There were no cases of impaired circulation, and subjective evaluations revealed satisfactory results in the fifth toe-spared group. Conclusions In cases with short and deviated sixth toes, sparing the fifth toe is an effective method of cosmetic treatment. The surgical results were satisfactory, with an improved appearance and no residual deformities.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.207-218
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• 2013

This study is based on a series of numerical modeling experiments to understand the circulation and its change in the Chunsu Bay (CSB), Yellow Sea of Korea. A skill analysis was performed for the tidal height and tidal current of the observation data using the amplitude and phase of the 4 major tidal constituents respectively for verification of modeling experimental results. As a result, most of the skill score was seen to be over 90%, so numerical model experiment results can be said to be in good agreement with the observed tidal height and tidal current. Tidal wave proceeded from the entrance of the CSB towards inside, and the tidal range gradually increased to the north. It took about 10 to 30 minutes for the tidal wave to reach to northern end. The tidal wave showed a characteristic to rotate counter-clockwise in the southern part. The tidal current flowed to the north-south direction along the bottom topography; the angle of the major axis appeared alongside the isobath. It showed the characteristics of reversing tidal current with the minor axis less than 10% of the major axis. The strength of the tidal residual current that is influenced by geographical factors including bathymetry and coastline showed the range of 1~30 cm/sec, greater in the south channel and smaller in northern Bay. Two pairs of cyclonic/anti-cyclonic eddies around Jukdo and 3~4 pairs of strong eddies at the southern part of CSB in hundreds of m to a few km size by relative vorticity derived from the tidal residual current.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.541-550
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• 1997

A least-square regression analysis is applied for the estimation of velocity streamfunction field based on discretely sampled current meter data. The coefficients of a streamfuunction that is expanded in terms of trigonometric basis function are obtained by enforcing the horizontal non-divergence of two-dimensional flow field. This method avoids Interpolation and gives a root-mean-square (rms) residual of fit which Includes the divergent part and noisiness of oceanic data. The Implementation of the method Is done by employing a boundary-fitted, curvilinear orthogonal coordinate which facilitates the specification of boundary conditions. An application is successfully made to the Texas-Louisiana shelf using the 32 months current meter data (31 moorings) observed as a part of the Texas-Louisiana Shelf and Transport Processes Study (LATEX). The rms residual of the fitting is relatively small for the shelf, which indicates the field Is Ivell represented by the streamnfunction.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.562-575
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• 2023

In an effort to improve water quality, the South Korean government has implemented measures to increase seawater circulation in Saemangeum Lake. We analyzed the effect of increasing the frequency of seawater circulation based on salinity levels and bottom water exchange in the lake, using an environmental fluid dynamics code model. When the sluice gate opening and shutting frequency increased from once to twice per day, the internal water level of Saemangeum Lake increased by up to ~0.7 m. The salinity increased by 2.12 psu near the western breakwater and decreased by 1.18 psu near the freshwater inlet. We analyzed the extent of bottom water exchange using a particle tracing method and observed that the residual rate of particles shallower than 5 m in water depth decreased by 2.52% in Case 2 (opening and shutting twice per day) compared to Case 1 (opening and shutting once per day). This indicates that increasing the frequency of sluice gate opening and shutting would promote enhanced bottom water exchange. Consequently, the increased salinity and bottom water exchange associated with increased seawater circulation are expected to improve water quality in Saemangeum Lake.