• 설비공학논문집
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• 제17권12호
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.249-252
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• 2002

Turbulent properties of the wake of a circular cylinder were measured The diameter of the cylinder is l0mm and the Reynolds number is 420. A new 3D-PTY system was constructed and a genetic algorithm (GA) was introduced in order to increase the number of instantaneous three-dimensional velocity vectors. In the GA two fitness functions were introduced in order to enhance the correspondences of the particles. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. More than 3000 instantaneous three-dimensional velocity vectors were obtained by the system. The database of the turbulent properties of the circular cylinder was constructed by the constructed 3D-PTV system.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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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.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2003년도 추계학술대회 논문집
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• pp.43-44
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• 2003

A 4D-PTV system was constructed. The measurement system consists of three high-speed high-definition cameras, Nd-Yag laser and a host computer. The GA-3D-PTV algorithm was used for completing the measurement system. A horizontal impinged jet flow was measured. The Reynolds number is about 40,000. 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 system.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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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.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.6-13
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• 2001

A new GA-3D-PTV technique has been constructed to measure an impinging jet. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. GA (Genetic Algorithm) was used based on one-to-one correspondences in order to take advantage of the combinatorial optimization in tracking the pairs of the whole particles of the two images having a time interval. Two fitness functions were introduced 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 constructed GA-3D-PTV system was applied in success to the measurement of flow characteristics of the impinging jet.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.548-554
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• 2001

A GA(Genetic Algorithm) based 3D-PTV technique has been developed. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. The fundamental of the developed technique was based on that one-to-one correspondence is found between two tracer particles selected at two different image frames taking advantage of combinatorial optimization of the genetic algorithm. The fitness function controlling reproductive success in the genetic algorithm was expressed by a kind of continuum theory on the sparsely distributed particles in space. In order to verify the capability of the constructed measurement system, a performance test was made using the LES data set of an impinging jet. The developed 3D-PTV system was applied to the measurement of flow characteristics of the wake of a circular cylinder.

• Journal of Advanced Marine Engineering and Technology
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• 제28권8호
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2444-2447
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• 2008

A new 3D-PTV algorithm (a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter (d=10mm) are 360, 720, 900 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image.