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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Visualization
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Journal DOI :
The Korean Society of Visualization
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Volume & Issues
Volume 4, Issue 2 - Dec 2006
Volume 4, Issue 1 - Jun 2006
Selecting the target year
Advanced Flow Visualization Technologies and Blue Ocean Strategy
Lee, Sang-Joon ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 3~5
Recently, the next-generation advanced flow visualization techniques such as holographic PIV, aynni.c PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced mea-surement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. They would be indispensable in solving complicated thermo-fluid flow problems not only in industrial fields such as automotive, space, electronics, aero- and hydro-dynamics. steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy technology etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe the nano- and bio-fluidic flow phenomena. In this article, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body are introduced as a blue ocean strategy.
Fabrication of Functional Microcapsule for Drug Delivery by using Droplet Phase Flow
Jeong, Eun-Ho ; Kim, Il ; Go, Jeung-Sang ; Kim, Kyung-Chun ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 6~10
The functional spherical microcapsules were produced through the innovative conjunction of the well-defined amphiphilic block copolymer and the stable droplet phase flow in the micro chemical plant. The microcapsules were formed to have hollow inner cavity and outer surface wall with nano-pores. To examine the potential of encapsulating foreign biochemical molecules, Congo-red dye was loaded into the microcapsule. The release performance in the specific surroundings such as temperature, pH and time was evaluated quantitatively.
Bubble Behavior in a Micro-Multi-Branched-Channel
Kim, Kyung-Chun ; Ryu, Geon-Ho ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 32~36
Recently there are many researches about single flow and two-phase flow phenomena in the mini and microchannel. But from this result the principle in the microchannel was not explained clearly. In this paper two-phase flow pattern was visualized in the micro-multi-branched-channel using a high speed camera. Microchannel was fabricated with PDMS and glass slide. The velocity profile was obtained by a Micro PIV. Then flow boiling at the near inlet area was occurred and vapor was moved in the micro-multi-branched-channel.
Development of Standard Experimental Apparatus for PIV Performance Evaluation
Sung, Jae-Yong ; Doh, Deog-Hee ; Lee, Suk-Jong ; Hwang, Tae-Gyu ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 37~43
An experimental apparatus for PIV performance evaluation has been developed. Stardard uncertainty of a two-dimensional cross-correlation PIV system was investigated based upon the standard experimental apparatus, which was devised to model the rigid body rotating flows. For the systematic analysis of the uncertainty introduced by each component (algorithm, CCD camera, frame grabber) of the PIV system, standard images are fed into the component independently. The standard experiments show that 53% of the uncertainty in the present PIV system results from the frame grabber but the errors from the algorithm and digital camera are ignorable.
Visualization Study on the Boundary Layer and Near-Wake of a Stationary Airfoil at Low Reynolds Numbers
Yang, Jae-Hun ; Chang, Jo-Won ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 44~50
A visualization study on the boundary layer and near-wake of an NACA 0012 airfoil was con-ducted in order to investigate the influence of boundary layer behavior on the near-wake at low Reynolds numbers. The present study is investigated at static angles of attack
by using a smoke-wire technique. The results of this study show that the laminar boundary layer on the airfoil surface is attached to the surface at
, and that laminar separation of boundary layer on the airfoil surface occurs at
. Furthermore, reattachment of the boundary layer occurs in the case of
. In the current study, the location of the laminar separation point moves upstream as the Reynolds number and the angle of attack increase.
Flow Visualization of an Unsteady Airfoil at Low Reynolds Numbers
Kim, Dong-Ha ; Chang, Jo-Won ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 51~58
A boundary layer visualization was carried out in order to investigate the influence of Reynolds number on an oscillating airfoil. An NACA 0012 airfoil is sinusoidally pitched at the quarter chord point with oscillation amplitude of
. A smoke-wire technique was employed to visualize the boundary layer and the near-wake. The freestream velocities are 1.98, 2.83 and 4.03m/s and corresponding chord Reynolds numbers are
, respectively. As the reduced frequency of K=0.1 is fixed, the corresponding frequency of an airfoil was adjusted in each case. The results reveal that the point at which the shear stress in an unsteady boundary layer separation disappears does not correspond with the position of the breakdown of the boundary layer, and that the breakdown of the boundary layer occurs further downstream.
Assessment of Interpolation Schemes in the Window Deformation PIV
Kim, Byoung-Jae ; Sung, Hyung-Jin ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 59~68
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
. 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.
Simultaneous Measurement of Size and Velocity of Microbubbles inside Opaque Tube Using X-ray PTV Technique
Kim, Seok ; Lee, Sang-Joon ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 69~75
The microbubbles were used in various fields, such as turbulent control, drag reduction, material science and life science. The X-ray PTV using X-ray micro-imaging technique was employed to mea-sure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Micro-bubbles of
diameter moving upward in an opaque tube (
=2.7mm) were tested. Due to the different refractive indices of water and air, phase contrast X-ray images clearly show the exact size and shape of over-lapped microbubbles. In all of the working fluids tested (deionized water, tap water, 0.01 and 0.10M NaCl solutions), the measured terminal velocity of the microbubbles rising through the solution was proportional to the square of the bubble diameter. The rising velocity was increased with increasing mole concentration. The microbubble can be useful as contrast agent or tracer in life science and biology. The X-ray PTV technique should be able to extract useful information on the behavior of various bio/microscale fluid flows that are not amenable to analysis using conventional methods.
The study on the measurement for the pressure drop and friction factor of corrugated metal pipes
Yun, Young-Sun ; Kang, Jun-One ; Yoo, Jai-Suk ; Kim, Hyung-Jung ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 76~80
The data for friction factor of the pipe correlated by Reynolds number and relative roughness have been reported well as a Moody chart. However, the results for corrugated shapes have been not investigated sufficiently. In this research, therefore, the pressure drop and friction factor are obtained. Flexible metal tubes with corrugations for the measurement are made of stainless steel plates. The kinds of tubes for the measurement are 5 annular types and helical types. The pressure drop & the velocity of the flow are obtained by micromanometer & digital pressure sensor, supplying dry air at several steps. Then the pressure drop is calculated for each tube, using the obtained data. The result shows that the pressure drop is strongly influenced by the viscous dissipation of kinetic energy due to the circulation of flows, rather than a viscous friction loss. The pressure drop increased consistently as the Reynolds number increases.
Study on the Air-Flow Separator of Light Particles Included in the Clod in the Production Process of Recycling Aggregates
Suh, Yong-Kweon ; Heo, Seong-Gyu ; Park, Yong-Gi ;
Journal of the Korean Society of Visualization, volume 4, issue 2, 2006, Pages 81~87
In this paper, we present flow patterns around and performance of an air-flow separator by using the numerical analysis. With this separator, particles of different density are to be separated by using the drag force from the air flow. The low-density particles are designed to be separated by using inhalation through holes on a rotating drum. To obtain the flow informations needed for determining the proper design parameters, we have performed numerical simulations by using a commercial code, ANSYS CFX. Various parameter set was tested and it was found that depending on the design of drums there exist critical parameter set regarding the attachment of light particles on the drum, which is prerequisite for the separation of materials. We present here the possibility of using the present design in separation of particles mixed in the clod for use in recycling.