Ensemble 3D PTV for high resolution turbulent statistics

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dc.contributor.author Agüera López, Nereida
dc.contributor.author Cafiero, Gioacchino
dc.contributor.author Astarita, Tommaso
dc.contributor.author Discetti, Stefano
dc.date.accessioned 2017-11-03T11:55:38Z
dc.date.available 2017-11-03T11:55:38Z
dc.date.issued 2016-12
dc.identifier.bibliographicCitation Measurement Science and Technology, 2016, vol. 27, n. 12, 124011
dc.identifier.issn 0957-0233
dc.identifier.uri http://hdl.handle.net/10016/25737
dc.description.abstract A method to extract turbulent statistics from three-dimensional (3D) PIV measurements via ensemble averaging is presented. The proposed technique is a 3D extension of the ensemble particle tracking velocimetry methods, which consist in summing distributions of velocity vectors calculated on low image density samples and then extract the statistical moments from the velocity vectors within sub-volumes, with the size of the sub-volume depending on the desired number of particles and on the available number of snapshots. The extension to 3D measurements poses the additional difficulty of sparse velocity vectors distributions, thus requiring a large number of snapshots to achieve high resolution measurements with a sufficient degree of accuracy. At the current state, this hinders the achievement of single-voxel measurements, unless millions of samples are available. Consequently, one has to give up spatial resolution and live with still relatively large (if compared to the voxel) sub-volumes. This leads to the further problem of the possible occurrence of a residual mean velocity gradient within the sub-volumes, which significantly contaminates the computation of second order moments. In this work, we propose a method to reduce the residual gradient effect, allowing to reach high resolution even with relatively large interrogation spots, therefore still retrieving a large number of particles on which it is possible to calculate turbulent statistics. The method consists in applying a polynomial fit to the velocity distributions within each sub-volume trying to mimic the residual mean velocity gradient.
dc.description.sponsorship Stefano Discetti was partially supported by Grant TRA2013-41103-P of the Spanish Ministry of Economy and Competitiveness. This grant includes FEDER funding. Nereida Agüera was supported by the fellowship Beca de colaboración 2015/16 of the Spanish Ministry of Education.
dc.format.extent 22
dc.format.mimetype application/pdf
dc.language.iso eng
dc.publisher IOP Publishing
dc.rights © 2016 IOP Publishing Ltd
dc.subject.other 3D PTV
dc.subject.other Turbulent statistics
dc.subject.other Reynolds stresses
dc.subject.other Volumetric PIV
dc.subject.other Particle image velocimetry
dc.subject.other Tracking velocimetry
dc.subject.other PIV
dc.subject.other Calibration
dc.title Ensemble 3D PTV for high resolution turbulent statistics
dc.type article
dc.subject.eciencia Aeronáutica
dc.identifier.doi https://doi.org/10.1088/0957-0233/27/12/124011
dc.rights.accessRights openAccess
dc.relation.projectID Gobierno de España. TRA2013-41103-P
dc.type.version acceptedVersion
dc.identifier.publicationissue 12
dc.identifier.publicationtitle Measurement science and technology
dc.identifier.publicationvolume 27
dc.identifier.uxxi AR/0000018445
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