• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3270-3275
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• 1994

Particle trajectory visualization using laser sheet was performed to investigate the corona wind flow interactions in the one-wire and two-wire type electrostatic precipitators. The corona wind generated by corona discharge was not negligible, and strong flow interactions took place owing to the induced circulatory cells. In the case of one-wire type, as the applied voltage was increased and the cross-section mean velocity was decreased, the effect of corona wind became active. In the case of two-wire type, if upstream discharge voltage was relatively higher than downstream discharge voltage, the effect of upstream corona wind was reduced.

• Journal of the Korean Society of Visualization
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• v.5 no.2
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• pp.48-55
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• 2007

Flow structure inside a refrigerating compartment of a scale-down display cooler model was investigated experimentally by using PIV (particle image velocimetry) method, a reliable velocity field measurement technique, in the present study. In addition, we also carried out flow visualization regarding flow structure and particle movement inside a display cooler by using a tracer method. As a result, the mean velocity field measurement shows a large scale vortical flow structure inside a refrigerating compartment due to strong entrainment flow, going through a base plate open gaps.

• Journal of the Korean Society of Visualization
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• v.11 no.2
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• pp.27-33
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• 2013

The inlet flow of centrifugal blower were quantitatively visualized using particle image velocimetry. Because the centrifugal blower system is one of the key parts of EV battery cooling system, the quantitative information of flow field of centrifugal blower is important to design and optimize the cooling system. Two types of inlet parts were used in this study. One is the straight inlet and the other is a bended one. The results showed the flow asymmetry exists in the straight model due to the pressure difference in the blower. In case of the bended one, the separation bubble and the increase of head loss appeared compared with the straight model.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.515-525
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• 2000

A new acoustic field visualization technique is introduced in this study. Small particles of which density is small enough to follow up the air used for the noise field visualization. In order to quantify the noise, PIV(Particle Imaging Velocimetry) has been constructed. When the driving frequency is in the vicinity of the resonance frequency of the simplified 2-dimensional muffler system, an acoustic streaming is shown and of which velocity distribution is obtained through PIV technique. It is experimentally proved that the present technique is able to visualize and quantify the acoustic fields.

• Journal of the Korean Society of Visualization
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• v.15 no.1
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• pp.32-40
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• 2017

Interaction between fluid and a rigid object is frequently observed in everyday life. However, it is difficult to simulate their interaction as the medium and the object have different representations. One of the challenging issues arises especially in handling deformation of the object visually as well as rendering haptic feedback. In this paper, we propose a real-time simulation technique for multimodal interaction between particle-based fluids and soluble solids. We have developed the dissolution behavior model of solids, which is discretized based on the idea of smoothed particle hydrodynamics, and the changes in physical properties accompanying dissolution is immediately reflected to the object. The user is allowed to intervene in the simulation environment anytime by manipulating the solid object, where both visual and haptic feedback are delivered to the user on the fly. For immersive visualization, we also adopt the screen space fluid rendering technique which can balance realism and performance.

• Journal of the Korean Society of Visualization
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• v.19 no.1
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• pp.36-42
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• 2021

This study measured the velocity of magnetic particles inside the power generation using external heat sources. Single Plane Illumination Microscopy (SPIM) was used to measure magnetic particles that are simultaneously affected by bubbly flow and magnetic field. It has the advantage of reducing errors due to particle superposition by illuminating the thin light sheet. The hydraulic diameter of the power generation is 3mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 200nm. The excitation and emission wavelengths are 530 and 650nm, respectively. In order to find out the flow characteristics, a total of four velocity fields were calculated in wide and narrow gap air bubbles, between the wall and the air bubble and just below the air bubble. Magnetic particles showed up to 8.59% velocity reduction in the wide gap between air bubbles due to external magnetic field.

• Journal of the Korean Society of Visualization
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• v.2 no.1
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• pp.12-17
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• 2004

The physical characteristics of soot near the soot inception point were investigated with various measurements. In-situ measurements of particle size and volume fraction were introduced based on time resolved laser-induced incandescence (TIRE-LII) and laser-induced ion mobility (LIIM). The one has more convenience and accuracy than conventional LII technique and the other works best for particle sizes of a few nanometers at high concentrations in a uniform concentration field. A complementary ex-situ measurement of particle size is nano differential mobility analyzer (Nano-DMA), which recently developed for measuring particle sizes between 2nm and 100nm and provides high-resolution size information for early soot. Particles will be also collected on transmission electron microscope (TEM) grids using rapid thermophoretic sampling and analyzed for morphology. These measurements will allow fresh and original insight into the characterizing soot inception process. The measured physical properties of incipient soot will clarify the controlling growth mechanism combined with chemical ones, and the dominant mechanism for soot modeling can be deduced from the information.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.32-38
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• 2019

The dynamic stability of swarms is crucial in preventing collisions in clustered flights and safely moving along a defined path. Although there have been many simulation studies on dynamic stability, there have not been many experimental studies using real clusters due to the difficulty in implementation. In this study, we constructed a particle-lattice structure simulating bird flocks or drone swarms, and conducted experiments within turbulent flow. We identified a criterion that describes dynamically stable particle-lattice structures. The stability increased as this newly defined spatial index increased.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.59-65
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• 2019

Phosphor particles ((Sr,Mg)₂ SiO₄:Eu²⁺ were suspended in deionized water in quartz cuvette and used for measuring liquid temperature field by using two-color-ratio method. In the temperature range of 23~77℃, it showed the relative error from 2.4% to 4% and the temperature sensitivity of 0.65 %/℃ at 30℃ and 0.95 %/℃ at 77 ℃. This performance is comparable to measurement techniques using thermographic liquid crystal or laser induced fluorescence or other thermographic phosphor particle. Among investigated potential error sources, the particle number density affected the intensity ratio and the temperature, but the effect of laser fluence was not evident.

• Journal of the Korean Society of Visualization
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• v.4 no.2
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• pp.59-68
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• 2006

We have evaluated the performances of the following six interpolation schemes used for win-dow deformation in particle image velocimetry (PIV): the linear, quadratic, B-spline, cubic, sinc, Lagrange interpolations. Artificially generated images comprised of particles of diameter in a range pixel were investigated. Three particle diameters were selected for detailed evaluation: pixel with a constant particle concentration $0.02particle/pixel^2$. Two flow patterns were considered: uniform and shear flows. The mean and random errors, and the computation times of the interpolation schemes were determined and compared.