• Journal of Environmental Science International
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• v.11 no.12
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• pp.1321-1326
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• 2002

A numerical model is investigated to predict a behavior of the gaseous volatile organic compounds and a subsurface contamination caused by them in the unsaturated zone. Two dimensional advective-dispersion equation caused by a density difference and two dimensional diffusion equation are computed by a finite difference method in the numerical model. A laboratory experiment is also carried out to compare the results of the numerical model. The dimensions of the experimental plume are 1.2m in length, 0.5m in height, and 0.05m in thickness. In comparing the result of 2 methods used in the numerical model with the one of the experiment respectively, the one of the advective-dispersion equation shows better than the one the diffusion equation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.174-184
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• 1998

In order to accumulate fundamental. data for control of fishes’ behavior at the real fishing ground, the fitness of the numerical model for describing the behavior of fishes was examined by the marine fish. Mullet, Mugil cephalus were used as experimental fishes. The numerical model of fishes’ behavior presented in our earlier paper was modified on the vertical movement of fish school. For the comparision of parameters of the modified numerical model between mullet and rainbow trout, the estimated values of parameters were identified with dimension. The fitness of the modified numerical model was examined by the comparision between experiment and simulation on the several indexes represented by fishes’ swimming characteristics. The obtained result are summarized a follows : 1. The non-dimensional parameter a’ of propulsive force and kb’ of interactive force by the experiment without model net showed a similarity, but the non-dimensional parameter k sub(c’) of schooling force for rainbow trout was lager than one for mullet and the non-dimensional parameter k sub(w’) of repulsive force for mullet was lager than one for rainbow trout. 2. The non-dimensional parameter a’ and k sub(b’) for rainbow trout by the experiment with model net were a little lager than ones for mullet, but non-dimensional parameter k sub(c’) and k sub(w’) for mullet were lager than ones for rainbow trout. 3. The non-dimensional parameter k sub(c’) and k sub(b’) showed the largest and the smallest value among the non-dimensional parameters for rainbow trout and mullet, respectively. 4. The fitness of the modified numerical model was confirmed by means of the compulsion between experiment and simulation on the swimming trajectory of fishes, the mean distance of individual from wall, the mean swimming speed, the mean swimming depth and the mean distance between the nearest individuals. Especially, the similarity of mean swimming depth was improved by using the modified numerical model.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.2
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• pp.66-77
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• 2018

This paper presents a parametric study on an oscillating water column (OWC) wave energy converter (WEC). This OWC has been planned for installation in the breakwaters on isolated islands located away from the mainland. Both a numerical analysis and a model experiment are utilized for determining a proper conceptual design for this purpose. Various design parameters, including the configurations and dimensions, are evaluated through the numerical analysis, which is based on a potential flow theory, and several design concepts are then selected as candidates. The model experiment using a 2D wave flume is conducted to evaluate the effects of the design parameters and compare the performances of the candidates. Based on the overall results of the numerical analysis and model experiment, a conceptual design of the OWC WEC applicable to a breakwater is selected.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.2
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• pp.103-111
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• 2006

To optimize the ventilation and smoke control systems in subway equipped with platform screen door, the technology to analyze the unsteady tunnel flow caused by running of train should be developed. The development of model experiment and numerical analysis technique with relation to unsteady flow of subway were presented. The pressure and air velocity changes in 1/20-scaling experiment unit were measured and results were comparied to those of 3-D unsteady numerical analysis applied with sharp interface method. The experimental and numerical results were quantitatively similar and it would be reasonable to apply sharp interface method to analyze the unsteady flow in subway equipped with platform screen door.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.129-137
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• 2006

In this research, we made a one and two-dimensional analysis of numerical data collected from the bend curvature of a bended river section. According to the result from the numerical analysis, the inflow ＆ output angle caused a water level deviation which increased with an increase of the flood discharge. From the water level deviation of our two-dimensional numerical model, we obtained the maximum slope of 6,67% when the inflow and output angle was 105 degrees and the flood discharge was 500 CMS. As for the right side, the differences with the one-dimensional numerical model were reduced when the angle was more than $90^{\circ}$. As for the left side the differences were reduced when the angle was more than $105^{\circ}$. For a river with more than 90 degrees bend curvature, a hydraulic experiment would be more appropriate than a numerical analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.723-728
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• 2014

Hydraulic experiments are performed in order to verify the swash effect of seashore structures installed to prevent scouring. However, a great deal of investment and time are required for producing the test apparatus and seashore structure used to perform the hydraulic experiment. The swash effect can be predicted, however, by using a numerical model and validation can be done based on comparisons of the numerical model and hydraulic experiment analysis results, thereby saving the cost and time required for producing the test apparatus and seashore structure. Taking a polyhedral rubble mound structure as the subject, this study performed a comparative analysis of wave run-up and run-down height of the numerical model interpretative results and the hydraulic experiment results, and validated the interpretative simulation wave test modeling technique. The study also predicted the swash effect by using the numerical interpretation approach method, whereby the volume ratio and friction area of the rubble mound were varied for different results.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.1-7
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• 2008

To investigate the appearance of cold water by upwelling effect near Ulsan-Gampo of the southeastern coast in Korea on June, 1999, we carried out a numerical experiment by 3-dimensional diagnostic numerical model. Appearance of cold water by the result of numerical experiment was due to upwelling by wind effect at 50-100m depth near Ulsan-Gampo coast. This result was mused by using a model to 2 times of existing wind magnitude near Busan, Ulsan and Gampo that is 5.0m/sec wind. Therefore, to illustrate the phenomenon of extraordinary marine environment like upwelling event and so forth, appropriate wind data at sea should be used instead of those on land.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.78-85
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• 2010

This study investigates reducing characteristics for the spreading of dredged soil and the diffusion of contaminant by silt protector curtain through three dimensional numerical experiment. The numerical medel is modified by combining the sediment transport characteristics for cohesive sediment into the previously developed model. Several numerical experiments have been given in order to investigate the reducing effect of silt protector using two dimensional numerical channel model under various parameters such as upstream flow velocity, depth of silt curtain and the position of dumped materials. Through the evaluation of several simulation results, we knew that the careful design has to be given in the determination of depth and position of silt protector.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.2
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• pp.162-169
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• 2007

This study is focused on the comparison of a 3 dimensional numerical and hydraulic model experiment for the flow phenomenon when a lock gate is opened. The lock gate is designed to discharge the flood flow rate at $218m^3/s$ of Solicheon at the Kun Jang national industry complex. The three dimensional ${\kappa}-{\epsilon}$ turbulent model of ANSYS CFX-10 of the computational fluid dynamics(CFD) program was used. The characteristics of CFX-10 are able to be simulated effectively for turbulent flow, especially the flow separation of the boundary layer of the two phase interface of air and water. The velocity and the flow pattern of the numerical model was showed to be similar to the results of the hydraulic model experiment.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.155-160
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• 2005

To purpose of this research is to develop the numerical model for simulating performance of ground heat exchanger with high prediction accuracy. This paper describes the development of a numerical model that simulates the heat transfer between ground and circulation water in ground heat exchanger. Furthermore, we propose the estimating technique of soil properties, such as thermal conductivity, heat capacity and hydraulic conductivity, based on ground investigation. Comparison between experiment and numerical analysis based on the model developed above was conducted under the condition of the experiment in 2004. The result of analysis agreed well with the experimental result.