• Ocean and Polar Research
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• v.21 no.2
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• pp.99-108
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• 1999

With sectional data obtained in September of 1987, 1988 and 1989 by quadrireciprocal ADCP measurement and CTD cast, the current structure, volume transport and vorticity in the Western Channel of the Korea Strait were studied. The characteristics of Tsushima Current water persisted throughout the summer especially in the homogeneous water of temperature $14-16^{\circ}C$ located at the depth of 50-100m below seasonal termocline. Thickness and velocity of the homogeneous layer are about 10-170m and 20-60cm/s. and the relative vorticity for this layer is shown to be nearly constant and it is smaller than the planetary vorticity. Potential vorticity of $2.70-7.10{\times}10^{-6}m^{-1}s^{-1}$ is found to be dependent mainly on planetary rather than on the relative vorticities. The Tsushima Current water represented by the homogeneous layer R14-16^{\circ}C$ may keep the potential vorticity at the area of strong current in the Strait. The ADCP current structure is similar to geostrophic current and the core of the current with the speed of 30-50cm/s is situated in the middle layer over the deep trough. With large tidal fluctuation the volume transport has mean value of 1.17sv which was about 40% larger than that of geostrophic calculation.

• Journal of Korea Water Resources Association
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• v.45 no.5
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• pp.473-480
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• 2012

A two-dimensional depth-integrated hydrodynamic and a depth-averaged passive scalar transport models were developed by using a Compact Finite Volume Method (CFVM) which can assure a higher order accuracy. A typical wave current interaction experimental data set was compared with the computed results by the proposed CFVM model, and resonable agreements were observed from the comparisons. One and two dimensional scalar advection tests were conducted, and very close agreements were observed with very little numerical diffusion. Finally, a turbulent mixing simulation was done in an open channel flow, and a reasonable similarity with LES data was observed.

• Journal of Environmental Impact Assessment
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• v.3 no.2
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• pp.47-56
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• 1994

AGNPS model is an event-based model to analyze nonpoint-source and to examine potential water quality problems from agricultural watershed. This model uses a square grid-cell system to represent the spatial variability of watershed conditions, and simulates runoff, sediment, and nutrient transport for each cell. AGNPS model was applied on Yeonwha watershed, and the test results were compared with the measured data for runoff volume, peak runoff rate, suspended solids, and phosphorus concentration. The watershed of 278.8 ha was divided into 278 cells, each of which was 1 ha in size. The coefficients of determination for runoff volume and peak flow were (0.893 and 0.801 respectively from regression of the estimated values on the measured values. The concentration of suspendid solid was increased but decreased that of phosphate with runoff volume.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.189-196
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• 2000

A numerical simulation was conducted to analyze the interaction of flame and vortices. The characteristic scales of flame and vortices were limited in the thin laminar flamelet regime. Within this regime, flame is assumed as discontinuity surface and its motion in flow field was described by G-equation instead of full governing equations. Additional approximations include distribution of line volume sources on flame surface to simulate effect of volume expansion. Contrast to previous calculations, current study employed vortex transport equation to evaluate attenuation and smearing of vortices. Two extreme conditions of frozen vortex and frozen flame were considered to validate the current method. Comparison with direct numerical simulation resulted in satisfactory quantitative agreement with higher computational efficiency which warrants the usefulness of the present model in more complex situation.

• Journal of computational fluids engineering
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• v.19 no.1
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• pp.15-20
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• 2014

Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code, termed SNUFOAM, which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley model ship. In results, the band width of the volume fraction contours between 0.1 to 0.9 at the hull surface was narrowed by considering the anti-diffusion term.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.260-268
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• 1998

A flow pattern and water exchange in Sagami Bay is examined using a barotropic hydraulic model. In the model experiments, the volume transports of the Kuroshio Through Flow were changed with time. The results of the model experiments show that when the volume transport is increased with time, water mass and vorticity are transferred to the inner part of the bay by wakes from the western part of the bay. In the case of decrease, as the wakes are ceased, the inner cyclonic circulation water is discharged to the outside of the bay by its southward extension through the Oshima eastern channel. It is found that the water exchange by the short-term variation of volume transport in time is about 20% of all the bay water.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.40
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• pp.147-167
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• 2008

This paper investigates changing business transaction under the e-commerce environment and their implications on freight transport industry with some case studies. It shows that an efficient and reliable delivery system is essential for e-commerce as business industries are faced with the stricter and more diversified demands of customer. In addition, many aspects of business practices such as small batch, customized production and just-in-time distribution in the e-commerce environment, in turn, bring about a number of changes in the volume and service patterns of freight transport. E-commerce requires longer transport distances and often higher delivery frequencies. It also entails to a certain extent a modal shift towards truck and air freight transport modes. On the one hand, the logistical requirements of e-commerce goods may stimulate greater complexity in existing supply chain management, causing higher costs. However it is true that the increased visibility of goods through more efficient information flow allows more efficient and effective transport management in the logistics system.

• Korean Membrane Journal
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• v.5 no.1
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• pp.61-67
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• 2003

Various characteristics of ion transport properties of a charged mosaic membrane with a parallel array of positive and negative functional charges were investigated, From the analysis of the volume flux, it was found that the salt flux based on nonequilibrium thermodynamics, preferential salt transport across the charged mosaic membrane. Transport properties of the magnesium sulfate(MgSO$_4$) and sucrose across the charged mosaic membrane were estimated. As a result, metal salts transport depended largely on the charged states and molecular weight otherwise nonelectrolyte solution was rejected under all experimental conditions. On the other hand, the reflection coefficient s indicated the negative value that suggested preferential material transport and was independent of charged mosaic thickness.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.140-145
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• 2010

Consolidation in cohesive soils mainly focuses on compressibility of soils, but it affects solute transport in some cases. The consolidation process takes on particular significance for fine grained soils at high water content, such as dredged sediments, but has also been shown to be important for compacted clay liners during waste filling operation. Numerical investigation using CST1 and CST2 was reviewed on consolidation-induced solute transport in this paper, especially with the development of CST2 model, verification by comparing experimental results with numerical simulations, and cases studies regarding transport in a confined disposal facility (CDF) and during in-situ capping. The importance of the consolidation process on solute transport is accessed based on simulated concentration or mass breakthrough curves. Results indicate that neglecting transient consolidation effects may lead to significant errors in transport analyses, especially with soft contaminated cohesive soils undergoing large volume change.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.4
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• pp.44-51
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• 2019

This study analyzes the trade patterns that occur between Korea and ASEAN countries through air transport, one of Korea's trade transport methods. In order to understand the detailed characteristics of the air transport sector, the dependent variables were analyzed by dividing them into amount and weight. As a result, the amount of exports, imports, and trade was proportional to GDP per capita representing income level, and inversely proportional to GDP representing national economic power. In terms of air transport weight, exports, imports and trade were all proportional to GDP representing economic power and inversely proportional to GDP per capita representing income levels. In addition, the national area acted as a factor to reduce the trade volume, and the number of airports and inland countries did not show any significant results.