• Journal of Korea Water Resources Association
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• v.38 no.8 s.157
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• pp.631-643
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• 2005

The objective of this study is to perform hydraulic and numerical model experiments of the flows in circulation-water-pump(CWP) chambers of combined cycle power plants (CCPP) to be built and to suggest improvement plans if the flows might cause a serious problem on the operation of CWPs. Hydraulic model was constructed in a scale of 1 to 20 using acrylic sheets and a two dimensional numerical model used was RMA2. To evaluate results of Hydraulic and numerical model experiments, evaluation criteria of flow conditions in the intake canal and CWP chambers were determined. Vertical vorticities obtained from numerical simulations for the initial plan of CCPPs were qualitatively compared with results of hydraulic model experiments and the formation possibility of a large scale vortex, one of the flow evaluation criteria, was evaluated. The initial plan was found not to satisfy the flow evaluation. Nine improvement plans were devised and numerically simulated. Four alternative plans among nine improvement plans were selected and hydraulically experimented. On the ground of the results of hydraulic model experiments, a final improvement plan, one of four improvement plants, was suggested. When CWP chambers and intake canals were designed with spatial constraints, flow separating wall and guide walls were found to improve flow conditions in CWP chambers.

• Fire Science and Engineering
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• v.14 no.2
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• pp.21-32
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• 2000

In this study, reduced-scale experiments as the alternative to a real-scale fire test were conducted to understand fire properties in tunnel, and their results were compared with those of numerical simulation. The 1/20 scale experiments were conducted under the Froude scaling since smoke movement in tunnel is governed by buoyancy farce. A numerical simulations were on performed 3D unstructured meshes with PISO algorithm and buoyant plume models. Results showed that data was in reasonable agreement with the numerical data of smoke velocity, temperature distribution, and clear height.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.25-32
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• 2012

To arrange effectively artificial reefs for marine afforestation, tidal currents were analyzed by numerical experiments. The numerical experiments were carried out by EFDC(Environmental Fluid Dynamics Code), and water column was vertically divided 5 layers. Tidal current patterns showed to be affected by main current at outside of study area, and circle currents of two were observed from analysis of residual currents. The calculated harmonic constants of tide and tidal current agreed well with those of observations at two stations for tide and two stations for tidal current. The model successfully reproduced the tidal current around the Geomoondo marine afforestation. It suggest that artificial reefs for marine afforestation should be installed belt zone at study area.

• The Journal of Korean Association of Computer Education
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• v.15 no.2
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• pp.67-73
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• 2012

The analytical experiments for fluid dynamics lead a sequence of complex scientific computations composing of numerical equations and require enormous computing resources with appropriate management tools. Currently most studies on e-Science environment for numerical studies focus on solving specific problems to drag out the best performance of matters and have less interest in providing a common framework to apply for diverse numerical domains in engineering education, especially for fluid dynamics. This paper presents an integrated e-Science experiment tool which could be easily applicable to solve various numerical analyses in fluid dynamics. As a proof-of-concept, an integrated e-Science framework with three numerical analyses has been designed and implemented over UNICORE that runs over grid computing environment.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.125-130
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• 2004

In this paper, the method of parameter estimation of a mathematical constitutive model blown as the smooth elasto-plastic cap model is studied. To predict the response of the real soil using this model, the eight parameters describing the constitutive equations have to be determined. First, experimental data are obtained from simple laboratory experiments such as one dimensional confined compression test in a consolidometer and drained triaxial compression test with the Ottawa sand f3r the reference value. Then, the numerical experiments are performed in the cap model with initial guessed parameters. The optimization method is utilized to fit the model response to experimental data by minimizing the error between the laboratory and numerical responses. Special attention is given to the parameter estimation procedure of numerical triaxial test due to the difficulty of the lateral strain measurements.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.922-934
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• 2010

To arrange artificial reefs for marine afforestation effectively, tidal currents were analyzed by numerical experiments, and particle tracking based on tidal currents was carried out to clarify the path of algae spores. The experiments were conducted by the Environmental Fluid Dynamics Code (EFDC), and water column was vertically divided into five layers. Tidal current patterns were showed to be affected by main currents outside of the study area, and two circle currents were observed during the analysis of residual currents. Particle tracking lasted 15 days at three installation places where artificial reefs for marine afforestation could be deployed. According to the results of the particle tracking experiment, particle movements at the No.1 and No. 3 stations were belt types along the coastal line. The No. 2 station documented an ellipse type movement 300~500m from coast line. These results suggest that artificial reefs for marine afforestation should be installed in the belt zones at of the No. 1 and No. 3 stations, and in the ellipse zone at the No. 2 station.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.1-14
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• 2006

This paper presents the techniques developed using the line source method to internally generate waves on an arc in a rectangular grid system. For five different types of wave generation layouts, quantitative experiments were conducted under the following conditions: the propagation of waves on a flat bottom, the refraction and shoaling of waves on a planar slope, and the diffraction of waves to a semi-infinite breakwater. Numerical experiments were conducted using the extended mild-slope equations of Suh et al. (1997). The fifth type of wave generation layout, consisting of two parallel lines connected to a semicircle, showed the best solutions, especially for a small grid size.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.4
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• pp.261-270
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• 1992

To investigate the flow patterns and diffusions in the Taean coastal waters of the eastern Yellow Sea, hydraulic and numerical experiments of tidal currents and diffusions of dye and cooling water were performed during spring tide along with field observations. Flow patterns obtained by the hydraulic and numerical experiments approximately coincide with those of the field observations. In the fold observations of tidal current, currents flow southwestward during the ebb tide, while currents flow northeastward during the flood tide. and the maximum velocity is 2.13 ㎧ toward WSW direction. The Eulerian diffusion coefficient estimated from field measmements of current is 7.82$\times$10$^{5}$ $\textrm{cm}^2$/s. Diffusion coefficients obtained from the area of dye plume in the model are given by the expression 0.18 $r^{4}$3/, and the coefficients have the range of 10$^{5}$ ~10$^{6}$ $\textrm{cm}^2$/s. These values are similar to the Eulerian diffusion coefficient estimated fram field measurements. Diffusion coefficients obtained in the hydraulic model are one to two orders higher than those obtained in the Onsan Bay in the eastern waters and two to three orders higher than those obtained in the Chinhae Bay in the southern waters of the Korean Peninsula. Diffusion patterns of cooling water by numerical experiments are similar to those of dye plume by hydraulic experiments. Both hydraulic and numerical experiment results of diffusions of dye plume and cooling water in the Taean coastal waters, have shown that the diffusion during the ebb tide is more prevalent than one during the flood tide.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.424-434
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• 2016

A few blast experiments are conducted to investigate the behavior of one-way reinforced concrete(RC) slabs under blast loading. Reflected blast characteristics as well as displacements and damage patterns of RC slabs are measured. Numerical models are also established in the software ANSYS AUTODYN to reproduce the experiments on RC slabs. The numerical models are distinguished from each other by different boundary conditions at the edges of RC slabs, which are assumed to reproduce displacements and damage patterns resulted from the experiments. The boundary condition of the experimental tests is estimated from the numerical simulation results. From the numerical simulation results, the boundary condition should be improved in order to measure the accurate maximum displacement in the experimental tests.

• Water for future
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• v.28 no.5
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• pp.129-140
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• 1995

In this study we derived steady-state relationships between surface saturation area and subsurface outflow, and between surface saturation area and soil moisture storage through numerical experiments with Richards equation on a hillslope. Numerical experiments analyzed the sensitivity of topographic and soil hydraulic properties on steady-state relationships between surface saturation area and subsurface outflow. And the power law for the extent of surface saturation area was determined as a function of subsurface outflow or soil moisture storage.