• Title/Summary/Keyword: 3D-PTV

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Measurements of the Cylinder Wake with a Volume PTV (High-Density 3D-PTV) (고밀도 3D-PTV (Volume PTV)에 의한 원주후류 측정 해석)

  • Hwang, T.G.;Cho, K.R.;Pyeon, Y.B.;Cho, Y.B.;Moon, K.R.;Jo, H.J.;Doh, D.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.88-91
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    • 2008
  • A Hybrid-Genetic-Algorithm based 3D-PTV has been constructed by introducing the conventional GA-3D-PTV. The measurement system consists of two-high-definition-cameras(1k ${\times}$ 1k), a Nd-Yag laser and a host computer. The system has been used to measure the wake of a cylinder. The Reynolds number is 1120. The structures of the wake have been quantified in detail than the results obtained ever before.

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Development of High-Definition 3D-PTV and its Application to High-Precision Measurements of a Sphere Wake (고해상 3차원 입자영상유속계 개발과 구 유동장 정밀해석 적용연구)

  • Hwang Tae-Gyu;Doh Deog-Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.12
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    • pp.1161-1168
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    • 2005
  • A Multi-Sectional 3D-PTV algorithm was developed to reduce the calculation time of the conventional GA-3D-PTV. The hardware system of the constructed 3D-PTV system consists of two high-speed cameras ($1,024\times1,018$ pixels, 60 fps), a metal halogen lamp (400W) and a host computer. The sphere(D=30mm) is suspended in a circulating water channel $(300mm\times300mm\times1,200m)$ and Reynolds number is 1,130. About 5,000 instantaneous three-dimensional velocity vectors have been obtained by the constructed 3D-PTV system. Turbulent properties such as turbulent intensity, Reynolds stress and turbulent kinetic energy were obtained. An eigenvalue analysis was carried out using the obtained instantaneous 3D velocity vectors to get the topological relations of the asymptotically stable critical point. Two structured shells, inner shell and outer shell, were found in the sphere wake and their motions were clarified by the measured data.

Development of a Stereoscopic PTV (스테레오 PTV법의 개발)

  • Doh Deog Hee;Lee Won Je;Cho Yong Beom;Pyeon Yong Beom
    • Journal of the Korean Society of Visualization
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    • v.1 no.1
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    • pp.92-97
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    • 2003
  • A new Stereoscopic PTV was developed using two CCD cameras, stereoscopic photogrammetry based on a 3D-PTV principle. Virtual images were produced for the benchmark test of the constructed Stereoscopic PTV technique. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on the Genetic Algorithm based 3D-PTV technique. The constructed Stereoscopic PTV technique was tested on the standard images of the impinged jet proposed by VSJ. The results obtained by the constructed system showed good agreements with the original data.

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3D-PTV Measurements of the Wake of a Goldfish (3D-PTV에 의한 금붕어 후류 계측)

  • Doh, D.H.;Hwang, T.G.;Chang, G.S.;Bang, Y.S.;Sang, J.W.;Kim, D.J.;Baek, T.S.;Cho, Y.B.;Pyun, Y.B.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.2054-2059
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    • 2003
  • 3D-PTV measurement was conducted on the wake of a goldfish in order to understand its swimming motions. The measurement system consisted of three CCD cameras, an image grabber, an Ar-Ion laser and a host computer. The flow properties of the wake of the goldfish were measured under three different velocities of the currents. Unsteady flow structures around the goldfish were quantitatively clarified using the time-consecutive instantaneous three-dimensional vectors obtained by the constructed 3D-PTV system.

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3D-PTV Measurements of the Statistical Turbulent Properties on the Wake of a Sphere (3D-PTV에 의한 구 후류 난류통계량 계측)

  • Doh, D.H.;Hwang, T.G.;Cho, Y.B.;Baek, T.S.;Pyun, Y.B.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1748-1753
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    • 2003
  • 3D-PTV measurement was conducted on the wake of a sphere. The Reynolds number is 1130 with the diameter(d=30mm). The measurement system consisted of three CCD cameras, an image grabber, an Ar-Ion laser and a host computer. An eigenvalue analysis was introduced for the analysis on the wake. Statistical turbulent properties were quantitatively clarified using the time-consecutive instantaneous three-dimensional vectors obtained by the 3D-PTV system. The spatial distributions of the sphere wake showed strong relations with spiral motions of the vortcies shedded from the surface of the sphere.

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High-Resoultion Stereoscopic PTV (고해상 스테레오PTV)

  • Doh D. H.;Lee W. J.;Cho Y. B.;Pyeon Y. B.;Jang S. W.
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.511-512
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    • 2002
  • A new stereoscopic PTV was developed using two CCD cameras, stereoscopic photogrammetry based on a 3D-PTV principle. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The constructed Stereoscopic W technique was tested on the standard images of the impinged jet proposed by VSJ. The results on the turbulent properties of the jet obtained by the constructed system showed a good agreement with the original LES data.

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Performance Tests on Stereoscopic PIV and Stereoscopic PTV using Standard Images (표준영상을 이용한 스테레오 PIV와 스테레오 PTV의 성능비교)

  • Doh, D.H.;Hwang, T.G.;Cho, Y.B.;Pyun, Y.B.
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1772-1777
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    • 2004
  • The performances of the newly constructed Stereoscopic PTV and Stereoscopic PIV which had been completed based on a 3D-PTV principle are tested using the Standard Images. Virtual images were produced for the benchmark tests of the constructed two Stereoscopic techniques. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The Standard data of LES are on the impinged jet proposed by VSJ. It is shown that the results obtained by Stereoscopic PTV have better reliability than those by Stereoscopic PTV.

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4-D PTV

  • Doh Deog Hee;OKAMOTO Koji
    • 한국가시화정보학회:학술대회논문집
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    • 2004.12a
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    • pp.33-40
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    • 2004
  • A 4D-PTV system was constructed. The measurement system consists of three high-speed high-definition cameras(1k x 1k, 2000fps), Nd-Yag laser(2000Hz) and a host computer. The GA-3D-PTV algorithm was used for completing the measurement system. The 4D-PTV is capable of probing the spatial distribution of velocity vectors of the flow field overcoming the temporal resolution of the characteristic turbulence length scales of the measured flow fields. A horizontal impinged jet flow (H/D=7) was measured. The Reynolds number is about 33,000. Spatial temporal evolution of the jet flow was examined and physical properties such as spatial distributions of vorticity and turbulent kinetic energy were obtained with the constructed.

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Measurements of a Round Jet with High-Definition 3D-PTV

  • Hwang, Tae-Gyu;Doh, Deog-Hee;Saga Tetsuo;Kenneth D. Kihm
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.8
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    • pp.1211-1224
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    • 2004
  • Two round jets. impinged and pulsed. were measured with high-resolution 3D-PTV technique. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. Two fitness functions were introduced in a genetic algorithm in order to enhance the correspondences of the particles. One was based on a concept of the continuum theory and the other one was based on a minimum distance error. The velocity profiles of the impinged jet obtained by the constructed 3D-PTV system were compared with those of LDV measurements made in this study. The head vortex of the jet was visualized by LIF and was reconstructed by the constructed high-resolution 3D-PTV system for comparisons.

4D-PTV(Dynamic 3D-PTV) Measurement on an Impinged Jet (4차원 입자영상유속계(다이나믹 3차원 입자영상유속계)에 의한 충돌분류측정)

  • Doh, Deog-Hee;Hwang, Tae-Gyu;Cho, Yong-Beom;Pyeon, Yong-Beom;Koji, Okamoto
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1767-1771
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    • 2004
  • A 4D-PTV system was constructed. The measurement system consists of three high-speed high-definition cameras, Nd-Yag laser(10mJ, 2000fps) and a host computer. The GA-3D-PTV algorithm was used to extract three-dimensional velocity vectors in the measurement volume. A horizontal impinged jet flow was measured with the constructed system. The Reynolds number is about 40,000. Spatial temporal evolution of the jet flow was examined in detail and physical properties such as spatial distributions of vorticity and turbulent kinetic energy were obtained with the constructed system.

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