A Study on Particle Identification in PTV-Particle Mask Correlation Method

Etoh, Takeharu; Takehara, Kohsei; Michioku, Kohji; Kuno, Satoshi

doi:10.3154/jvs.16.1supplement_239

Cited by 6 publications

(6 citation statements)

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“…Images were taken in the same manner as for vessel M. A laser light sheet made by a 4 W Ar-ion laser was utilized for the velocity measurement in the Z-Y plane. The particle images were extracted and the location was determined by a PMC algorithm (12) . Particle velocities were measured using a four step tracking algorithm (13) .…”

Section: Experimental Methods 221 Visualization and Velocity Measurementmentioning

confidence: 99%

Effects of Ultrasound on Behavior of Fine Solid Particles in a Solid-Liquid Mixture (Horizontal Irradiation in a Stationary Solid-Liquid Mixture)

Ohta

Makara

Hirobe

2007

JFST

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In a solid-liquid two-phase flow, the separation of particles or a reduction of particle concentration is often desired. Utilization of ultrasound has been considered as one technique for the separation of particles. Particles are known to aggregate due to the radiation pressure of ultrasound. However, the effect of ultrasound including cavitation on particle behavior is not well understood. Thus, we horizontally irradiated water with aluminum particles having a density of 2720 kg/m 3 and diameters of 50 to 150 µm or smaller aluminum powder (flakes) in a rectangular vessel by ultrasound at frequencies of 23 kHz or 100 kHz. In this way, a standing wave was formed. The following results were obtained. For ultrasound of 100 kHz, the aluminum powder aggregates in vertical bands. When acoustic cavitation existed at the frequency of 23 kHz, we noticed that the aluminum particles aggregate as clumps near antinodes of the sound pressure profile because of the flow induced by acoustic cavitation. When the particles are continuously provided in a relatively high concentration, particle clumps form and remain. Then, the particle clumps become larger and suddenly fall faster than the surrounding small particles. Such phenomena repeat themselves periodically. At relatively low concentrations, particle clumps do not become large and remain stationary at the same positions.

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Section: Experimental Methods 221 Visualization and Velocity Measurementmentioning

confidence: 99%

Effects of Ultrasound on Behavior of Fine Solid Particles in a Solid-Liquid Mixture (Horizontal Irradiation in a Stationary Solid-Liquid Mixture)

Ohta

Makara

Hirobe

2007

JFST

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“…In this regard, a breakthrough idea is the particle-maskcorrelation method proposed by Etoh and Takehara (1998), which is basically a sort of Gaussian peak-fitting scheme. The mask is scanned over the entire image in order to detect the peaks of image intensity, which then correspond to the particle centres.…”

Section: Introductionmentioning

confidence: 99%

Particle-tracking velocimetry with new algorithms

Ohmi

2000

Meas. Sci. Technol.

221

173

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New algorithms for particle-tracking velocimetry are proposed and tested with typical particle images showing two-dimensional fluid flows. There are new ideas not only in the algorithm of the particle tracking itself but also in that of the individual-particle detection. The performance of the particle tracking is much improved by the new relaxation method and that of the individual-particle detection by the use of the dynamic threshold-binarization method. The special concern of the authors about the new algorithms is the applicability of particle-tracking velocimetry to high-density particle images, contrary to what is usually believed regarding this type of particle-imaging velocimetry. These new algorithms are first tested in synthetic images with a variety of particle parameters and then in other types of experimental visualizations showing jet and wake flows.

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“…The particle detection was done using the particle mask correlation method [8], where a typical brightness pattern of a particle image (called particle mask) is generated and every recorded frame is scanned from pixel to pixel to find occurrences of this pattern.…”

Section: Particle Detectionmentioning

confidence: 99%

“…[8] proposed therefore to generate the particle mask using such a distribution of the intensities. However, it often occurs that the shape of the particle images becomes elliptical instead of circular due to the inhomogeneous illumination or due to high velocities.…”

Section: Particle Detectionmentioning

confidence: 99%

Particle tracking velocimetry (PTV) and its application to analyse free surface flows in laboratory scale models

Sokoray-Varga

Józsa

2008

Per. Pol. Civil Eng.

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The methodology and application of particle tracking velocimetry (PTV) for surface flow velocity measurements are presented in a conventional laboratory scale model characterised both by large vortices and turbulence, making use of the fact that PTV allows to take reliable measurements in flows exposed to strong deformations typical in turbulent shear layers.The experimental setup included a river reach with main channel and wide floodplain of different roughness. Surface PTV measurements were carried out by a CCD camera with 30 frames per second frame rate and vertical camera axis.In the evaluation of the recordings an algorithm suitable to be applied in flows with strong strains was needed, capable to find corresponding particles even by highly deformed neighbourhoods. For this aim a modification of the so-called velocity gradient tensor method was used.The reconstructed velocity fields were used first to visualize the mean flow field, then to identify and investigate the various flow structures by means of the swirling strength analysis. KeywordsParticle Tracking Velocimetry (PTV) · PIV · laboratory scale model · surface velocity measurement AcknowledgementWe would like to thank the Institute for Hydromechanics at University of Karlsruhe for providing insight into their PIV laboratory works. Special thanks to Wernher Brevis for instructing and explaining algorithmic details of his PTV code, inspiring then the one used in the present work. The research was partly funded by the Hungarian Scholarship Board Office.

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A Study on Particle Identification in PTV-Particle Mask Correlation Method

Cited by 6 publications

References 0 publications

Effects of Ultrasound on Behavior of Fine Solid Particles in a Solid-Liquid Mixture (Horizontal Irradiation in a Stationary Solid-Liquid Mixture)

Effects of Ultrasound on Behavior of Fine Solid Particles in a Solid-Liquid Mixture (Horizontal Irradiation in a Stationary Solid-Liquid Mixture)

Particle-tracking velocimetry with new algorithms

Particle tracking velocimetry (PTV) and its application to analyse free surface flows in laboratory scale models

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