• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.153-158
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• 2000

Flow visualization and PIV measurements were conducted to investigate the flow characteristics of multi-channel with inclination angle. The water flow seeded with tiny vegetable powder as tracers revealed details of flow field. The PIV measurement to acquire multi-point velocity data simulatneously was carried out at three space of plates for 5, 10, and 15mm with variation of inlet flow rates of $0.25m^3/h$ and <$0.5m^3/h.$ Experiment results show that space of plates acts a significant role in separating process.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.263-266
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• 2007

The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile aerodynamics, creation of new materials since it can create an extremely high-pressure state in very short time. Two-stage light gas gun is being employed most extensively. The present experimental study has been conducted to develop a new type of ballistic range which can easily perform a projectile simulation. The experiment is conducted to find out the dependence of various parameters on the projectile velocity. The pressure in high-pressure tube, pressure of diaphragm rupture and projectile mass and piston mass are varied to obtain various projectile velocities. The flow field is visualized to see flow around projectile.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.382-389
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• 2000

The instantaneous and ensemble averaged flow characteristics of a round jet issuing normally into a crossflow was studied using a flow visualization technique and Particle Image Velocimetry measurements. Experiments were performed at a jet-to-crossflow velocity ratio, 3.3, and two Reynolds numbers, 1050 and 2100, based on crossflow velocity and jet diameter. Instantaneous laser tomographic images of the vertical center plane of the crossflow jet showed that there exist very different natures in the flow structures of the near field jet even though the velocity ratio is the same. It was found that the shear layer becomes much thicker when the Reynolds number is 2100 due to the strong entrainment of the inviscid fluid by turbulent interaction between the jet and crossflow. The mean and second order statistics were calculated by ensemble averaging over 1000 realizations of instantaneous velocity fields. The detail characteristics of mean flow field, stream wise and vertical r.m.s. velocity fluctuations, and Reynolds shear stress distributions were presented. The new PlV results were compared with those from previous experimental and LES studies.

• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.207-215
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• 2005

We present a finite difference solution for electrokinetic flow in rectangular microchannels encompassing Navier's fluid slip phenomena. The externally applied body force originated from between the nonlinear Poisson-Boltzmann field around the channel wall and the flow-induced electric field is employed in the equation of motion. The basic principle of net current conservation is applied in the ion transport. The effects of the slip length and the long-range repulsion upon the velocity profile are examined in conjunction with the friction factor. It is evident that the fluid slip counteracts the effect by the electric double layer and induces a larger flow rate. Particle streak imaging by fluorescent microscope and the data processing method developed ourselves are applied to straight channel designed to allow for flow visualization of dilute latex colloids underlying the condition of simple fluid. The reliability of the velocity profile determined by the flow imaging is justified by comparing with the finite difference solution. We recognized the behavior of fluid slip in velocity profiles at the hydrophobic surface of polydimethylsiloxane wall, from which the slip length was evaluated for different conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.5
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• pp.650-658
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• 1997

Analysis and control of intake charge motion such as swirl and tumble are very important factors in improving the gasoline engine performance. In this paper, single-frame PTV (particle tracking velocimetry) is used to investigate intake tumble patterns in a steady flow test rig of gasoline engine with dual-intake-valve and pent-roof combustion chamber. Intake tumble pattern is quantified in accordance with blockage ratio of TIV (tumble intensifying valve) with single- frame PTv.The view of the instantaneous 2-D velocity field gives a realistic understanding of in-cylinder flow field. Thus it is confirmed that PTV is a effective tool in engine design. In conventional port, two tumble structures appear clearly, and the larger one is observed under the exhaust valve side and the smaller is right below the intake valve side. The larger vorticity is observed in TIV port, thus it is concluded that TIV have an effect on intensified tumble motion in cylinder flow.

• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.107-110
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• 2005

In this study a newly designed and electro-osmotic micro-mixer is proposed. This design is comprised of a channel and metal electrodes attached in the local side wall surface, To investigate the flow patterns a numerical method is employed. To obtain the flow patterns numerical computation are performed by using a commercial code, CFD-ACE. The fluid-flow solutions are then cast into studying the characteristics of stirring with aid the Mixing index. Focus is given the effect on the electro osmotic flow characteristics under the curvature variation in the microchannel with the local of the electric field

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.123-127
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• 2007

The effect of axial slit wall of outer cylinder on Taylor-Couette flow was experimentally investigated. The axial slits were azimuthally located along the inner wall of outer cylinder and the number of slits was 6, 9 and 18. The radius ratio and aspect ratio of the experimental models was 0.825 and 48, respectively. We used PIV method to measure the flow field and applied refractive index matching method to resolve the image distortion due to the complex model geometry. The results showed the effect of slit on the flow transition is increased as the number of slit increased. When the model has 6 slits, there were hardly the effect of axial slit wall and the flow transition happened at the same Reynolds number of plain smooth wall model case.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.687-688
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• 2008

Air flow of inside automobile HVAC module has been visualized using a high-resolution PIV technique with varying the temperature operation mode. The PIV system consists of a 2-head Nd:YAG laser(125 mJ), a high-resolution CCD camera(2K x 2K), optics and a synchronizer. A real automobile HVAC module was used directly with slight modification for clear optical windows. Some parts of the HVAC module casing were replaced with transparent windows for capturing flow images with laser light sheet beam illumination. Time-averaged velocity field were measured in three temperature control modes. Flow characteristics of the air-conditioned air flow in the automobile HVAC system were evaluated.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.125-131
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• 2005

The purpose of the present study is to examine the flow characteristics of ER fluids between 2 port and 3 port rectangular tube brass electrodes. ER fluid is made silicon oil mixed with $2-3wt\%$ starch having hydrous particles. Flow visualization of the ER fluids were obtained by CCD camera measuring those of the clusters using an image processing technique. This research found the flow $rate(Q_L)$ with 0 kV /mm, 0.5kV/mm and 1.0kV/mm for $Q_L\;=\;0,\;0$ and $5.73cm^3/s$. When the strength of the electric field increased, the cluster of ER fluids are clearly strong along the rectangular tube and the flow rate(Q) decreased.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.261-266
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• 2006

In this study, a scaled model chamber was built to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model by visualization equipment with laser apparatus. Four different kinds of measuring area were selected as experimental condition Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system and its software adopting two-frame grey-level cross correlation algorithm. The flow pattern reveals the large scale counter-clockwise forced-vortex rotation at center area.