LAGRANGIAN STATISTICS FOR DENSELY-SEEDED FLOWS USING SCANNING PARTICLE IMAGE VELOCIMETRY. Kozul, M.; Koothur, V.; Worth, N., A.; and Dawson, J., R. Technical Report
LAGRANGIAN STATISTICS FOR DENSELY-SEEDED FLOWS USING SCANNING PARTICLE IMAGE VELOCIMETRY [pdf]Paper  abstract   bibtex   
We propose a novel robust three-dimensional particle tracking technique based on a scanning laser setup. The method yields Lagrangian statistics in densely-seeded turbulent flows with good spatial and temporal resolution, overcoming some of the inherent difficulty with line-of-sight based volumetric methods. To do this we have developed an effective triangulation method greatly reducing ghost particle reconstruction using images from two cameras. A laser sheet is rapidly traversed ('scanned') across a measurement volume illuminating only a thin slice of the flow at a time. Particle images are taken at closely-spaced, overlapping nominal laser sheet locations giving multiple intensity recordings for each individual particle. The laser-sheet intensity varies as a Gaussian across its thickness, which is here exploited to deduce the particle's probable location along the scan direction to sub-sheet number resolution by fitting a similarly-Gaussian profile to its multiple intensity recordings. Following successful reconstruction of a time series of three-dimensional particle fields, particle tracks are formed from which all components of Lagrangian velocity and acceleration are calculated. The method is presently verified via synthetic experiment using a database born of direct numerical simulation, and is intended for high-Reynolds number experimental flows.
@techreport{
 title = {LAGRANGIAN STATISTICS FOR DENSELY-SEEDED FLOWS USING SCANNING PARTICLE IMAGE VELOCIMETRY},
 type = {techreport},
 id = {fea36189-1c68-3759-95e7-10e80fdd818b},
 created = {2020-05-26T18:31:29.992Z},
 accessed = {2020-05-26},
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 last_modified = {2020-05-26T18:31:34.141Z},
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 abstract = {We propose a novel robust three-dimensional particle tracking technique based on a scanning laser setup. The method yields Lagrangian statistics in densely-seeded turbulent flows with good spatial and temporal resolution, overcoming some of the inherent difficulty with line-of-sight based volumetric methods. To do this we have developed an effective triangulation method greatly reducing ghost particle reconstruction using images from two cameras. A laser sheet is rapidly traversed ('scanned') across a measurement volume illuminating only a thin slice of the flow at a time. Particle images are taken at closely-spaced, overlapping nominal laser sheet locations giving multiple intensity recordings for each individual particle. The laser-sheet intensity varies as a Gaussian across its thickness, which is here exploited to deduce the particle's probable location along the scan direction to sub-sheet number resolution by fitting a similarly-Gaussian profile to its multiple intensity recordings. Following successful reconstruction of a time series of three-dimensional particle fields, particle tracks are formed from which all components of Lagrangian velocity and acceleration are calculated. The method is presently verified via synthetic experiment using a database born of direct numerical simulation, and is intended for high-Reynolds number experimental flows.},
 bibtype = {techreport},
 author = {Kozul, Melissa and Koothur, Vipin and Worth, Nicholas A and Dawson, James R}
}
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