• 제목, 요약, 키워드: PIV

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표준영상을 이용한 2차원 PIV와 3차원 PIV 성능시험 (Performance Test on 2-Dimensional PIV and 3-Dimensional PIV Using Standard Images)

  • 황태규;도덕희
    • 대한기계학회논문집B
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    • v.28 no.11
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    • pp.1315-1321
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    • 2004
  • Quantitative performance test on the conventional 2D-PIV and the hybrid angular 3D-PIV(Stereoscopic PIV) was carried out. LES Data sets on an impinging jet which are provided on the webpage(http://www.vsj.or.jp/piv) for the PIV Standard Project were used for the generation of virtual images. The generated virtual images were used for the 2D-PIV and 3D-PIV measurements test. It has been shown that the results obtained by 2D-PIV on average values are slightly closer to the LES data than those obtained by 3D-PIV, but the turbulent properties obtained by 2D-PIV are largely underestimated than those obtained by 3D-PIV.

표준화상을 이용한 2차원 PIV와 3차원 PIV계측 및 성능비교검정 (Performance Test of 2-Dimensional PIV and 3-Dimensional PIV using Standard Images)

  • 도덕희;황태규;송주석;백태실;편용범
    • 대한기계학회:학술대회논문집
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    • pp.646-651
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    • 2003
  • Quantitative performance test on the conventional 2D-PIV and the hybrid angular 3D-PIV (Stereoscopic PIV) was carried out. LES Data sets on an impinging jet which are provided on the webpage(http://www.vsj.or.jp/piv) for the PIV Standard Project were used for the generation of virtual images. The generated virtual images were used for the 2D-PIV and 3D-PIV measurements. The measurement results showed that the results obtained by 2D-PIV on average values are closer to the LES data than those obtained by 3D-PIV, but the turbulent properties obtained by 2D-PIV are largely underestimated than those obtained by 3D-PIV.

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상호상관 PIV를 이용한 예혼합 분무화염의 계측에 관한 연구 (A Study on Measurement of Premixed Spray Flame using Cross-correlation PIV)

  • 양영준;김봉환
    • 에너지공학
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    • v.14 no.4
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    • pp.259-267
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    • 2005
  • 예혼합 분무화염의 상세한 연구기구를 관찰하기 위하여 예혼합 분무화염 중의 분무단면상의 확대촬영과 또한 연소시의 순간적 이차원 유동장을 얻기 위해 미소시간차를 가진 2연속 분무단면 화상에 대해 상호 상관 PIV를 적용하였다. PIV에 통상 사용되어지는 펄스 레이저가 아닌 연속발진 레이저를 PIV에 적용하는 기법 등을 나타내었다. 또한 통계적 PIV 해석법을 이용하여 얻은 상호상관 PIV의 결과를 PDA에 의해 측정된 결과와 비교하여, 상호상관 PIV는 PDA의 계측에 의한 결과와 잘 일치한다는 결론에 이르렀다. 연속발진 레이저를 이용한 상호상관 PIV를 예혼합 분무화염에 적용하여 본 연구에서 적용한 기법이 분무화염의 구조를 관찰하는데 매우 유용함을 검증하였다.

에코 PIV를 이용한 맥동 유동에서의 in vitro 전단률 측정 연구 (Non-Invasive Measurement of Shear Rates of Pulsating Pipe Flow Using Echo PIV)

  • 김형범;정인영
    • 대한기계학회논문집B
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    • v.28 no.12
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    • pp.1567-1572
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    • 2004
  • Although accurate measurement of velocity profiles, multiple velocity vectors, and shear stress in arteries is important, there is still no easy method to obtain such information in vivo. This study shows the utility of combining ultrasound contrast imaging with particle image velocimetry (PIV) for non-invasive measurement of velocity vectors. The steady flow analytical solution and optical PIV measurements (for pulsatile flow) were used for comparison. When compared to the analytical solution, both echo PIV and optical PIV resolved the steady velocity profile well. Error in shear rate as measured by echo PIV (8%) was comparable to the error of optical PIV (6.5%). In pulsatile flow, echo PIV velocity profiles agreed well with optical PIV profiles. Echo PIV followed the general profile of pulsatile shear stress across the artery but underestimated wall shear at certain time points. These studies indicate that echo PIV is a promising technique for the non-invasive measurement of velocity profiles and shear stress.

Development of higher performance algorithm for dynamic PIV

  • NISHIO Shigeru
    • 한국가시화정보학회:학술대회논문집
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    • pp.25-32
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    • 2004
  • The new algorithm for higher performance of dynamic PIV has been proposed. Present study considered mathematical basis of PIV analysis for multiple-time-step images and it enables us to analyze the high time-resolution PIV, which is obtained by dynamic PIV system. Conventional single pair image PIV analysis gives us the velocity field data in each time step but it sometimes contains unnecessary information of target flow. Present technique utilize multi-time step correlation information, and it is analyzed.

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단일 광경로 스캔PIV기법의 개발 (Development of single optical axis scanning PIV method)

  • 김형범;정인영;이상혁;류청환
    • 한국가시화정보학회:학술대회논문집
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    • pp.6-10
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    • 2005
  • PIV(Particle image velocimetry) presents the flow velocity of whole flow fields in a fraction of a second. Conventional PIV method uses two optical axis configuration during the image grabbing process. That is, the illumination plane and the recording plane must be parallel. This configuration is very natural to grab the whole field without the image distortion. In the real problem, it is often to meet the situation which this configuration is hard to be fulfilled. In this study, we developed new PIV method which only uses single optical axis to grab the particle images. This new PIV method become possible by utilizing the scanning method similar to echo PIV technique. One particle image of scanning PIV consists of scanned several line images and by repeating this scanning process, two particle images were grabbed and processed to produce the velocity vectors.

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X-ray PIV 기법의 개발과 혈액 유동에의 적용연구 (Development of X-ray PIV Technique and its Application to Blood Flow)

  • 김국배;이상준
    • 대한기계학회논문집B
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    • v.29 no.11
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    • pp.1182-1188
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    • 2005
  • An x-ray PIV (Particle Image Velocimetry) technique was developed to measure quantitative information on flows inside opaque conduits and on opaque-fluid flows. At first, the developed x-ray PIV technique was applied to flow in an opaque Teflon tube. To acquire x-ray images suitable for PIV velocity field measurements, refraction-based edge enhancement mechanism was employed using detectable tracer particles. The optimal distance between with the sample and detector was experimentally determined. The resulting amassed velocity field data were in reasonable agreement with the theoretical prediction. The x-ray PIV technique was also applied to blood flow in a microchannel. The flow pattern of blood was visualifed by enhancing the diffraction/interference -bas ed characteristic s of blood cells on synchrotron x-rays without any contrast agent or tracer particles. That is, the flow-pattern image of blood was achieved by optimizing the sample (blood) to detector distance and the sample thickness. Quantitative velocity field information was obtained by applying PIV algorithm to the enhanced x-ray flow images. The measured velocity field data show a typical flow structure of flow in a macro-scale channel.

Miniature Stereo-PIV 시스템의 개발과 응용 (Development and Application of a Miniature Stereo-PIV System)

  • 김경천;;김상혁
    • 대한기계학회논문집B
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    • v.27 no.11
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    • pp.1637-1644
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    • 2003
  • Stereoscopic particle image velocimetry is a measurement technique to acquire three dimensional velocity field by two cameras. With a laser sheet illumination, the third velocity component can be deduced from out-of$.$plane velocity components using a stereoscopic matching method. Most industrial fluid flows are three dimensional turbulent flows, so it is necessary to use the stereoscopic PIV measurement method. However the existing stereoscopic PIV system seems hard to use since it is very expensive and complex. In this study we have developed a Miniature Stereo-PIV(MSPIV) system based on the concept of the Miniature PIV system which we have already developed. In this paper, we address the design and some primitive experimental results of the Miniature Stereo-PIV system. The Miniature Stereo-PIV system features relatively modest performances, but is considerably smaller, cheaper and easy to handle. The proposed Miniature Stereo-PIV system uses two one-chip-only CMOS cameras with digital output. Only two other chips are needed, one for a buffer memory and one for an interfacing logic that controls the system. Images are transferred to a personal computer (PC) via its standard parallel port. No extra hardware is required (in particular, no frame grabber board is needed).

Three-Dimensional Characterization of Strong Recirculating Flow by Stereoscopic PIV

  • Ikeda, Yuji;Palero, Virginia;Sato, Kei;Nakajima, Tsuyoshi
    • 한국연소학회지
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    • v.7 no.1
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    • pp.37-43
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    • 2002
  • Spray characteristics in the swirling flow were investigated by Stereoscopic PIV. Spatial spray structures were measured by PIV as well as PDA in order to understand stable flame stabilization. The feasibility study of Stereoscopic PIV in spray flame was also demonstrated. The size and location of recirculation flow were measured. The stereoscopic PIV could provide 3-D flow fluctuation that cannot be measured by convectional measurement systems.

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유체기계연구에서의 PIV의 적용 (Application of PIV to Fluid-Machinery Studies)

  • 이영호
    • 유체기계공업학회:학술대회논문집
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    • pp.188-195
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    • 1997
  • The application of PIV to the studies of fluid-machines, especially focused on turbo-machinery is reviewed by scrutinizing the previous investigation. Owing to the inevitable high-speed analysis of turbo-machinery consisting of rotating impellers, the importance of optical setups to cope with illumination problem is frequently mentioned as main ingredient affecting the PIV performance. And the acquisition of the relative velocity and absolute velocity is determined mainly by the optical recording conditions. A few studies cast satisfactory extension of the PIV data to quantitative pressure estimation and related noise assessment.

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