• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.490-498
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• 2004

This paper measures the forced convective heat transfer from heated cylinder to air flow in a rectangular duct at Re$_{D}$ =2,337, 4,589, 6,621 and 7,944 through experiments. And the heat transfer is computed by 3-D numerical computation in which various turbulent models are applied. It is shown through the comparison of experimental and computed data that numerical computation with standard k-$\varepsilon$ model predicts the experimental data most accurately. Furthermore, the correlation from the computed heat transfer is almost similar to that from the experiment when Re$_{D}$ is greater than 4,589. In addition, the correlation of McAdams is the closest to that from experimental data among various correlations from literature in the range of Reynolds number.ber.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.443-450
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• 2009

This study has dealt with the ice making characteristics in a rectangular vessel cooled from below direction with experiment and numerical analysis. The experiment and numerical analysis were carried out under the following conditions which are the cooling wall temperatures of -5[$^{\circ}C$], -10[$^{\circ}C$], and -15[$^{\circ}C$]. The temperature profile of non-frozen layer was calculated by numerical analysis as the form of non-dimensional temperature. From this study, it is cleared that the existence of natural convection is clearly known. And also the non-dimensional freezing amount was derived from experimental result. This correlation equation will give a useful information to the designers of ice making system.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1135-1140
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• 2009

The present study has been studied on a thermal and flow characteristic of the microchannel waterblock with pass variations in 8 samples. Results of a numerical analysis using the CFX-11 were compared with results of an experiment. Numerical analysis and experiment were conducted under an input power of 150 W, inlet temperature of $35^{\circ}C$ and mass flow rates of $0.7{\sim}2.0\;kg/min$. The numerical results showed reasonably good agreement with the experimental results within about $3{\sim}5%$. Also, the numerical results showed that the sample 2 types with the 2 pass gave better performance than the sample 1 types with the 1 pass from the viewpoints of heat transfer and pressure drop.

• Transactions of Materials Processing
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• v.11 no.5
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• pp.414-422
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• 2002

Most of numerical analyses for injection molding have been based on the Hele Shaw's approximation: two-dimensional flow analysis. In some cases, that approximation causes significant errors due to loss of geometrical information as well as simplification of the flow characteristics along the thickness direction. The present work covers numerical analyses of injection molding using three-dimensional solid elements. The accuracy of the analysis results has been verified through some numerical examples in comparison with the classical shell-based approach. The Proposed approach is then applied to predict product defects and to improve flow characteristics for a precision electronics part. In addition, design of experiment has been utilized in order to find the optimal process conditions for better product quality.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.68-75
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• 2002

Most of numerical analyses for injection molding have been based on the Hele Shaw's approximation: two-dimensional flow analysis. In some cases, that approximation causes significant errors due to loss of geometrical information as well as simplification of the flow characteristics along the thickness direction. The present work covers numerical analyses of injection molding using three-dimensional solid elements. The accuracy of the analysis results has been verified through some numerical examples in comparison with the classical shell-based approach. The proposed approach are then applied to predict product defects and to improve flow characteristics for a precision electronics part. In addition, design of experiment has been utilized in order to find the optimal process conditions for better product quality.

• 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.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.101-110
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• 2005

In this paper, the experiments have been conducted to measure the residual velocity for 3.5g steel ball perforating light weight metal plates of aluminum alloy and magnesium alloy. Non-contact electro-magnetic sensors were used to measure the velocity of steel ball before/after perforating plates. The thicknesses of specimens used were about 2.8mm and 4.8mm. The impact velocities of steel ball were from 662m/s to 3594m/s. With same conditions, numerical analysis using Autodyn 2D has been conducted. The results of numerical analysis corresponded with those of experiments. Also, It is suggested that the difference between the residual velocity of experiment or numerical analysis and that of THOR experimental equation of BRL grew smaller as the impact velocity were increased.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2995-2996
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• 2007

We found that there exists a flow inside a droplet in AC electrowetting, which is distinct from DC electrowetting. In order to investigate the origin of the flow inside the droplet, we performed an experiment and numerical simulation. It is conjecture, based on the results of the experiment and numerical simulation, the flow is caused by the so called induced-charge electroosmosis at high frequencies, and by droplet oscillation at low frequencies.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1167-1174
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• 2008

Vertical drain method, which is one of the soft ground improvement methods, shorten s drain path to accelerate consolidation process and is applied in many sites. At a recent, composite discharge capacity experiment that analyze discharge amount by consolidation behavior with overburden pressure of soft ground in laboratory, simulates similarly with actuality. Geotechnical engineering problems such a s soft ground improvement are solved by numerical analysis by development of computer and numerical analysis techniques. Numerical analysis does that result is contrary by user's inexperience for choice of constitution model and application of analysis method. Therefore, this thesis experiments on composite discharge capacity test and study discharge capacity of drain and consolidation behavior of soft ground installed prefabricated vertical drain boards. Also, This thesis studied reasonable input parameters and constitution model by compare results of composite discharge capacity test and numerical analysis using PLAXIS that is 2D finial element numerical analysis program.

• Journal of Korea Water Resources Association
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• v.44 no.6
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• pp.461-470
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• 2011

Abrupt and gradual levee breach analyses on the flat domain were implemented by laboratory experiments and numerical simulations. To avoid the reflective wave from the side wall the experiment was performed in a large domain surrounded by waterway. A numerical model was developed for solving the two-dimensional gradual levee breach flow. The results of the numerical simulation developed in this study showed good agreement with those of the experimental data. However, even if the numerical schemes effectively replicated the trends of the observed water depth for the first shock, there were little differences for the second shock. In addition, even though the model considered the Smagorinsky horizontal eddy viscosity, the location and height of the hydraulic jump in the numerical simulation were not fairly well agree with experimental measurements. This shows the shallow water equation solver has a limitation which does not exactly reproduce the energy dissipation from the hydraulic jump. Further study might be required, considering the energy dissipation due to the hydraulic jump or transition flow from reflective wave.