• Title/Summary/Keyword: PIV

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Advanced Flow Visualization Technologies and Blue Ocean Strategy (첨단 유동가시화 기법들과 Blue Ocean 전략)

  • Lee, Sang-Joon
    • Journal of the Korean Society of Visualization
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    • v.4 no.2
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    • pp.3-5
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    • 2006
  • 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.

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Advanced Flow Visualization Technologies and Blue Ocean Strategy (첨단 유동가시화 기법들과 Blue Ocean 전략)

  • Lee, Sang-Joon
    • 유체기계공업학회:학술대회논문집
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    • pp.145-146
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    • 2006
  • Recently, the next-generation advanced flow visualization techniques such as holographic PIV, dynamic PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced measurement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. These would be indispensable in solving complicated thermo-fluid flow problems not only in the 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 engineering 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 most complicated nano- and bio-fluidic phenomena. In this presentation, 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 will be introduced as a blue ocean strategy.

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Measurement of Thermal Flow in a Hele-Shaw Convection Cell Using Holographic Interferometry and PIV Technique (홀로그래픽 간섭계와 PIV를 이용한 Hele-Shaw Convection Cell 내부 열유동 해석)

  • Kim Seok;Lee Sang-Joon
    • 한국가시화정보학회:학술대회논문집
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    • pp.35-38
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    • 2002
  • Variations of temperature and velocity fields in a Hele-Shaw Convection Cell (HSC) were measured using a holographic interferometry and PIV technique with varying Rayleigh number. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow at high Rayleigh numbers. Two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed to measure the temperature field variations of HSC convective flow. In the double-exposure method, unwanted waves can be eliminated and reconstruction images are clear, but transient flow structure cannot be observed clearly. On the other hand, transient flow can be observed and reconstructed well using the real-time method. PIV results show that flow inside the HSC is periodic and the oscillating state is well matched with the temperature field results. The holographic interferometry and PIV techniques employed in this study are useful for analyzing the unsteady convective thermal fluid flows.

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PIV Measurements of the Pressure Driven Flow Inside a T-Shaped Microchannel (T형 마이크로채널 내부 압력구동 유동의 PIV 계측)

  • Choi Jayho;Lee In-Seop
    • Proceedings of the KSME Conference
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    • pp.423-426
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    • 2002
  • A custom micro-PIV optics assembly has been used to measure the flow field inside a T-shaped microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of $420,\;40,\;60{\mu}L/hr$. The microchannels are fabricated with PDMS with a silicon mold, then $O_2-ion$ bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results show PIV results with vector-to-vector distances of $2{\mu}m$ with 32 pixel-square interrogation windows at $50{\%}$ overlap.

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A Study on the Evaluation of Interpolation Methods in PIV (PIV에서의 보간기법의 평가에 관한 연구)

  • 최장운;조대한;최민선;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.4
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    • pp.90-100
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    • 1996
  • To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.

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Stereoscopic micro-PIV measurements of jet flow (미세제트 유동의 Stereoscopic micro-PIV측정)

  • Yu, Cheong-Hwan;Kim, Hyoung-Bum
    • Journal of the Korean Society of Visualization
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    • v.5 no.1
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    • pp.43-48
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    • 2007
  • Micro-PIV(particle image velocimetry) has been widely used to measure the velocity of micro flow. Although this micro-PIV method can give accurate 2D instantaneous velocity information of mea-surement plane, it cannot resolve the out of plane component of velocity vectors. Lots of the micro fluidic devices generate three-dimensional flow and 3D measurement of velocity is useful to understand the physics of micro flow phenomena. In this study, we constructed stereoscopic micro-PIV(SMPIV) system and applied this method to the impinging micro jet flow. The results show that this method can produce accu-rate 3D reconstruction of micro jet flow.

An experimental analysis of the fluid flow in an automobile HVAC system using a PIV technique (PIV기법을 이용한 차량용 공조 시스템 내부유동에 대한 실험적 연구)

  • Ji, Ho-Seong;Kim, Bo-Ram;Lee, Sang-Joon
    • 한국가시화정보학회:학술대회논문집
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    • pp.92-96
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    • 2007
  • Internal flow characteristics for an automobile HVAC have been investigated using a high-resolution PIV technique. The PIV system consists of a 2-head Nd:YAG laser(125 mJ), a high-resolution CCD camera($2K\;{\times}\;2K$), optics and a synchronizer. An automobile HVAC module was used directly. Only the casing was remodeled transparently for capturing flow image and laser sheet beam illumination. Time-averaged velocity field were measured in three temperature control mode. For three temperature control modes, the internal flow characteristics for an automobile HVAC system were evaluated from PIV results..

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Measurement of Flow Field in a Domestic Hot-Water Pump by PIV (PIV에 의한 가정용 온수펌프의 유동장 계측)

  • Lee, H.;Im, Y. C.;Kim, J. H.;Lee, Y. H.
    • 유체기계공업학회:학술대회논문집
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    • pp.264-271
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    • 1999
  • The present experimental study is aimed to investigate the flow characteristics of the high-speed flow field within hot-water pump by PIV(Particle Image Velocimetry). As multi-point simultaneous velocity acquisition, 2-D PIV system based upon the two-frame gray-level cross correlation method is adopted using PC frame-grabber and simple video system. Gated image intensifier CCD Camera to cope with illumination problem is arranged for accurate PIV measurement of high-speed complex flow. The velocity vector distribution, velocity profile, and kinetic energy are represented quantitatively at the full-scale region for the deeper understanding of the unsteady flow characteristics in a pump.

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Flow Characteristics around a NACA0012 Airfoil by PIV (PIV에 의한 NACA0012 익 주변의 유동특성)

  • Choi, M.S.;Cho, D.H.;Lee, Y.H.
    • Journal of Power System Engineering
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    • v.3 no.1
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    • pp.29-37
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    • 1999
  • The flow characteristics of a NACA0012 airfoil was investigated in rectangular water circulating channel. The flow patterns around an airfoil at various angles of attack between $0^{\circ}\;and\;30^{\circ}\;at\;Re=1.91{\times}104$ were visualized and measured with 2-D PIV system and laser sheet illumination. Flow behaviors such as velocity distribution, kinetic energy and flow separation etc. around an airfoil were obtained by means of 2-D PIV system. The behaviors show the difference of flow pattern clearly and separation phenomena become more active with increasing angle of attack.

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The Study on Two-color PIV Algorithm for a Measurement of Droplet Velocity (액적의 속도 측정을 위한 이색 PIV 알고리즘 연구)

  • Lee, K.H.;Lee, C.S.;Oh, S.I.
    • Journal of ILASS-Korea
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    • v.4 no.1
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    • pp.13-18
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    • 1999
  • It has been known that spray characteristics have an important effect on the mixture formation and directly influence the engine performances and the emissions. Up to now, the measurement of droplet size is well developed such as PDPA and PMAS though the behavior of small droplets during secondary atomization is not clear. Particle image velocimetry(PIV), a planar measuring technique, is a very efficient tool for studying complicated behavior and a fast and reliable method to track numerous droplets during injection. In this study, two-color scanning PIV is designed to obtain quasi-instantaneous two dimensional velocity data by using he-ion laser, rotating mirror and beam splitter. This PIV method which has high temporal and spatial resolution provides the information about the small complex droplet behavior.

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