• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.624-633
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• 2016

Although a number of information is emerging in the big data era and studies on the infographic studies for delivering it effectively are becoming an issue, the visualization study on the numerical information delivered through the credit card statement is very poor compared to its importance. The effective visualization method following each information characteristics was by analyzing the numerical information types focusing on the credit card statement. The type of the figure information classified into the comparative analysis, progress of time change, proportion, relationship, scope, and distribution, and it was made into the graph form proper to the nature of each information to study the most effective and ideal visual form. Therefore, this study is significant because it suggests a control point of the visualization by pointing out an effective visual form for delivering the numerical information that appears on the credit card statement with the figure characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.134-141
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• 2006

Surface deflections have a great effect on the external appearance of automobiles. Usually, they are occurred on large flat panels containing sudden shape changes and of very small size about $\pm$30$\sim$300$\mu$m. Since the current numerical method is not sufficient for predicting these defects, the correction of these defects still depends on trial and error, which requires a great deal of time and expense. Consequently, developing the numerical method to predict and prevent these defects is very important far improving cosmetic surface qualities. In this study, an evaluation system that can analyze surface deflections using numerical simulation and a visualization system are reported. To calculate the surface deflections numerically, robust algorithms and simulation methodologies are suggested and to visualize them quantitatively, the curvature variation algorithm is proposed. To verify the developed systems, the experimental die of the handle portion of exterior door is analyzed. The results showed that the experimental and simulational visualization are in good agreement. Compensation methods to correct the surface deflections are also tested. The evaluation system proposed in this paper could be used to predict and minimize the occurrence of surface deflections in die manufacturing.

• Journal of the Korean Society of Visualization
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• v.14 no.2
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• pp.12-17
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• 2016

In this work, we investigate the flow velocity controllability of a diffuser-type multiple hydrofoil duct by experimental and numerical flow visualization approaches. The flow velocity controllability is analyzed by changing the angle of the hydrofoil near the outlet, which is the diffuser, while the incoming flow velocity is 0.6 m/s in the experiment. When the diffuser angle is changed from 0 to 7.5 degree, the maximum velocity inside the duct is varied from 1.35 m/s to 1.52 m/s. Also, it is shown from the numerical analysis that the maximum velocity is varied from 1.09 m/s to 1.17 m/s in the same condition. Thus, the aspect of the acceleration in the duct due to the increase of the diffuser angle is similar between the both approaches. Therefore, the multiple hydrofoil duct can be used to control the flow speed inside the duct for continuously extracting power close to a rated capacity.

• Journal of the Korean Society of Visualization
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• v.10 no.3
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• pp.25-29
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• 2012

This paper introduces a new parameter to design the $2{\times}2$ microfluidic centrifuge with single flow rotation positioned at the center of microchamber. The dimensional centrifugal acceleration momentum flux which is defined as the interfacial momentum flux divided by distance from the center of the chamber explains the flow rotation and its threshold provides a reference to expect single flow rotation. Through the numerical and experimental visualization of the flow rotation, the number and position of flow rotation in the $2{\times}2$ microfluidic centrifuge were examined. At a channel width of $50{\mu}m$ and chamber width of $250{\mu}m$, single flow rotation was obtained over at a Reynolds number of 300, while at a channel width of $100{\mu}m$ and chamber width of $500{\mu}m$, single flow rotation did not appear. The numerical analysis showed that the threshold centrifugal acceleration momentum flux to obtain single flow rotation was $3500kg/m{\cdot}s^2$.

• Journal of the Korean Society of Visualization
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• v.16 no.2
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• pp.7-15
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• 2018

The fluid-flow characteristics of flue-gas-recirculation (FGR) system can have a significant effect on system efficiency of a sintering plant. The flow characteristics in the system were investigated. A sintering plant with FGR system was modeled. Numerical visualization was performed and flow characteristics were analyzed. Characteristics of the flow distribution of the branch ducts, the inflow of air into the recirculating hood, and the flow in the hood were discussed. Based on the results three suggestions were proposed: (1) distribution of branch duct flowrate upstream, (2) installation of external air ducts in the hood, and (3) installation of baffles at the hood corners. The suggestions were tested numerical and experimental visualization methods. The suggestions were effective and confirmed to be applicable to the actual sinter plant.

• Journal of the Korean Society of Visualization
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• v.17 no.1
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• pp.85-92
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• 2019

Numerical visualization is conducted to confirm the variation of flow characteristics and pressure drop by the shape of channels on the cathode flow path in hydrogen fuel cells for unmanned aerial vehicles(UAVs). Generally, a light-weight fan is commonly used rather than a heavy air compressor at UAVS. However, in case of blower fan, a large pressure drop in the flow path causes the blocking of the oxygen supply to the fuel cell. Therefore, the uniformity of flow inside the cathode has to be achieved by changing the shape of the cathode. The flow channel, the duct shape, and the diameter of the fan are changed to optimize the flow path. As a result, it is confirmed that the optimal flow path can decrease the velocity difference between the center and outer flow by 1.8%. However, It should be noted that the channel size can increase the pressure drop.

• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1548-1554
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• 2001

Flow patterns and dynamic properties of two-stage Weis-Fogh type ship propulsion mechanism are studied by a discrete vortex method. To study mutual interference between two wings, two cases are con sidered - wing motions with the same and reverse phases. The predicted flow patterns correspond to the available flow visualization results. Time histories of thrust and drag coefficients are also calculated, and the interference between the two wings are numerically clarified.

• Journal of computational fluids engineering
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• v.11 no.3 s.34
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• pp.37-45
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• 2006

In this study we present the numerical methods that can be used in visualization of the flow and mixing patterns in a cavity driven by a top lid. The basic flow field within the cavity has been obtained by using a simple numerical scheme. The invariant manifold also called unstable manifold was then attained to represent the mixing pattern within the cavity. It was shown that care must be taken in calculating the trajectories of the fluid particles especially near corners of the cavity. The numerical results show excellent agreement with those obtained experimentally by other research group.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.45-50
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• 2005

Characteristics of flows at T-junction duct with and without orifices are investigated in this paper. Experiments and PIV visualization were carried out for several flow rates. Two-dimensional PIV experimental apparatus was decided by numerical analysis. PIV visualization was also coded to visualize flow fields at junctions for two-dimensional case. For the PIV visualization system, Grey-Level Cross-Correlation particle tracking algorithm was used to calculate the flow fields. Vinyl chloride polymer particles of $100{\sim}150{\mu}m$ of diameter are used in this visualization. The PIV visualization results showed relatively good agreement with Experimental data.

• Journal of the Korean Society of Visualization
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• v.9 no.4
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• pp.28-34
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• 2011

A volumetric gear pump is often used in extensive industrial applications to provide both high pressure and sufficiently high flow rate by physical displacement of finite volume of fluid with each revolution. Template mesh function in commercial CFD software, PumpLinx, by which 3-D meshes in the complex region between rotor and housing can be readily generated was employed for 3-D flow simulations. For cavitation analysis full cavitation model was included in 3-D simulations. The results showed high pulsation in pressure and flowrate which is implicated in pump vibration and noise. A model test for cavitation visualization was conducted and the results showed good qualitative agreement with numerical prediction.