• Title, Summary, Keyword: PIV

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

  • Lee, Y. H.
    • 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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Three-Dimensional Characterization of Strong Recirculating Flow by Stereoscopic PIV

  • Ikeda, Yuji;Palero, Virginia;Sato, Kei;Nakajima, Tsuyoshi
    • Journal of the Korean Society of Combustion
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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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Stereoscopic PIV (스테레오 PIV)

  • Doh, D.H.;Lee, W.J.;Cho, G.R.;Pyun, Y.B.;Kim, D.H.
    • Proceedings of the KSME Conference
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    • pp.394-399
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    • 2001
  • A new stereoscopic PIV is introduced. The system works with CCD cameras, stereoscopic photogrammetry, and a 3D-PTV principle. Virtual images are produced for the construction of a benchmark testing tool of PIV techniques. The arrangement of the two cameras is based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors are based on 3D-PTV technique.

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Measurement of turbulent jet flow using dynamic PIV technique (Dynamic PIV를 이용한 난류 제트유동 해석)

  • Lee Sang-Joon;Jang Young-Gil;Kim Seok
    • 한국가시화정보학회:학술대회논문집
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    • pp.36-39
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    • 2005
  • Information on temporal evolution of whole velocity fields is essential for physical understanding of a complicated turbulent flow and was obtainable using dynamic PIV because of advances of high-speed imaging technique, laser and electronics. A dynamic PIV systme consists of a high-speed CMOS camera having $1K\times1K$ pixels resolution at 1 KHz and a high-repetition Nd:Yag pulse laser. In order to validate its performance, the dynamic PIV system was applied to a turbulent jet whose Reynolds number is about 3000. The particle images of $1024\times512$ pixels were captured at a sampling rate of 4 KHz. The dynamic PIV system measured successfully the temporal evolution of instantaneous velocity fields of the turbulent jet, from which spectral analysis of turbulent structure was also feasible.

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Flow Characteristics for PIV Visualization at Junction Duct (PIV 가시화에 의한 합류덕트에서의 유동특성)

  • Kim, M.K.;Kwon, O.B.;Bae, D.S.
    • Journal of Power System Engineering
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    • v.9 no.4
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    • pp.45-50
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    • 2005
  • Characteristics of flows at T-junction duct with and without orifices are investigated in this paper. Experiments and PIV visualization were carried out for several flow rates. Two-dimensional PIV experimental apparatus was decided by numerical analysis. PIV visualization was also coded to visualize flow fields at junctions for two-dimensional case. For the PIV visualization system, Grey-Level Cross-Correlation particle tracking algorithm was used to calculate the flow fields. Vinyl chloride polymer particles of $100{\sim}150{\mu}m$ of diameter are used in this visualization. The PIV visualization results showed relatively good agreement with Experimental data.

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Development of Standard Experimental Apparatus for PIV Performance Evaluation (PIV 성능시험을 위한 표준실험장치 개발)

  • Sung, Jae-Yong;Doh, Deog-Hee;Lee, Suk-Jong;Hwang, Tae-Gyu
    • Journal of the Korean Society of Visualization
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    • v.4 no.2
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    • pp.37-43
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    • 2006
  • 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.

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Development of the Scanning PIV Method with Single Optical Axis (단일 광경로 스캐닝 PIV기법 개발)

  • Kim, Hyoung-Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.2
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    • pp.181-187
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    • 2007
  • 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 when this configuration is hard to be fulfilled. In the present study, the new PIV method which uses only single optical axis to grab the particle images is developed. This new PIV method becomes possible by utilizing the scanning method similar to the echo PIV technique. One particle image of the 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. An optimization study was performed to find parameters which minimize the measurement errors. The effects of particle diameter, beam overlap ratio and particle number density were investigated.

Flow Visualization in the Branching Duct by Using Particle Imaging Velocimetry (입자영상유속계를 이용한 분기관내 유동가시화)

  • No, Hyeong-Un;Seo, Sang-Ho;Yu, Sang-Sin
    • Journal of Biomedical Engineering Research
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    • v.20 no.1
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    • pp.29-36
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    • 1999
  • The objective of this study is to analyse the flow field in the branching duct by visualizing the flow phenomena using the PIV system. A bifurcation model is fabricated with transparent acrylic resin to visualize the whole flow field with the PIV system. Water was used as the working fluid and the conifer powder as the tracer particles. The single-frame and two-frame methods of the PIV system and 2-frame of the grey level correlation method are applied to obtain the velocity vectors from the images captured in the flow filed. The velocity distributions in a lid-driven cavity flow are compared with the so-called standard experimental data, which was obtained from by 4-frame method in order to validate experimental results of the PIV measurements. The flow patterns of a Newtonian fluid in a branching duct were successfully visualized by using the PIV system and the sub-pixel and the area interpolation method were used to obtain the final velocity vectors. The velocity vectors obtained from the PIV system are in good agreement with the numerical results of the 3-dimensional branch flow. The results of numerical analyses and the PIV experiments for the three-dimensional flows in the branch ing duct show the recirculation zone distal to the branching point and the sizes of the recirculation length and height of the tow different methods are in good agreement.

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Comparison of Velocity Fields of Wake behind a Propeller Using 2D PIV and stereoscopic PIV (2D PIV와 stereoscopic PIV 기법으로 측정한 프로펠러 후류의 속도장 비교 연구)

  • Paik Bu-Geun;Lee Sang-Joon
    • 한국가시화정보학회:학술대회논문집
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    • pp.23-26
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    • 2002
  • The phase-averaged velocity fields of 3 dimensional turbulent wake behind a marine propeller measured by 2D PIV and stereoscopic PIV(SPIV) were compared directly. In-plane velocity fields obtained from the consecutive particle images captured by one camera in 2D PIV have perspective errors due to out-of-plane motion. However, the perspective errors can be removed by measuring three component velocity fields using SPIV method with two cameras. It is also necessary to measure three components velocity fields for the investigation of complicated near-wake behind the propeller for the suitable propeller design. 400 instantaneous velocity fields were measured for each of four different blade phases of $0^{\circ},\;18^{\circ},\;36^{\circ}C\;and\;54^{\circ}$. They were ensemble averaged to investigate the spatial evolution of the propeller wake in the downstream region. The phase-averaged velocity fields show the viscous wake developed along the blade surfaces and tip vortices were formed periodically. The perspective errors caused by the out-of-plane motion was estimated by the comparison of 2D PIV and SPIV results. The difference in the axial mean velocity fields measured by both techniques are nearly proportional to the mean out-of-plane velocity component which has large values in the regions of the tip and trailing vortices. The axial turbulence intensity measured by 2D PIV was overestimated since the out-of-plane velocity fluctuations influence the in-plane velocity vectors and increase the in-plane turbulence intensities.

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