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On the use of finite mixtures to improve the physical interpretation of a ground vortex flow

2017-03-12Journal article Restricted access
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dc.contributor.authorSilva, A. R. R.
dc.contributor.authorPanão, Miguel
dc.contributor.authorBarata, Jorge M M
dc.date.accessioned2018-05-10T08:35:06Z
dc.date.available2018-05-10T08:35:06Z
dc.date.issued2017-03-12
dc.description.abstractLaser-Doppler measurements of the velocity characteristics of a ground vortex flow resulting from the collision of a wall jet with a boundary layer are analyzed using advanced statistical tools, namely finite mixtures of probability density functions. These are determined by the best fitting to experimental results using a Bayesian approach based on a Markov Chain Monte Carlo (MCMC) algorithm. This approach takes into account eventual multimodality and heterogeneities in velocity field distributions. Therefore, it provides a more complete information about heterogeneous velocity distributions and its corresponding characteristic velocities and turbulent fluctuations. The ground vortex flow investigated is generated by a wall jet-to-boundary layer velocity ratio of 2. The results evidence how finite mixtures are able to reconstruct the measured probability distribution in the form of a mathematical probability density function. This allows to improve the physical interpretation of the ground vortex flow through quantifying its complex structure, which is particularly relevant to VSTOL aircraft flows. Namely, identify the separation point oscillation region, and the enlargement of the region comprising the effect of collision between wall jet and boundary layer in planes moving away from the wall. Also, in the collision zone, following a conventional statistical analysis, the rms velocity fluctuation (u′) appears to be overestimated for the horizontal component due to the measured velocity range oscillating between positive and negative values. The results evidence how U‾ and u′ provide an idea of the flow dynamics, but their use is limited and an important amount of information associated with the highly curved flow complexity is lost. This prevents distinguish the magnitude of velocity fluctuations according to the flow direction, and the endorsement of anisotropy near the collision region, justifying the possibility of being numerically simulated.pt_PT
dc.description.versioninfo:eu-repo/semantics/publishedVersionpt_PT
dc.identifier.citationAndré R.R. Silva, Miguel R.O. Panão, Jorge M.M. Barata, On the use of finite mixtures to improve the physical interpretation of a ground vortex flow, Experimental Thermal and Fluid Science, Volume 85, 2017, Pages 344-353, DOI: 10.1016/j.expthermflusci.2017.03.017pt_PT
dc.identifier.doi10.1016/j.expthermflusci.2017.03.017pt_PT
dc.identifier.issn0894-1777
dc.identifier.urihttp://hdl.handle.net/10400.6/4749
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.publisherElsevierpt_PT
dc.relation.publisherversionhttp://www.sciencedirect.com/science/article/pii/S0894177717300808pt_PT
dc.subjectVSTOLpt_PT
dc.subjectGround vortexpt_PT
dc.subjectWall jetpt_PT
dc.subjectBoundary layerpt_PT
dc.subjectStatistical analysispt_PT
dc.subjectFinite mixturespt_PT
dc.subjectBayesian approachpt_PT
dc.subjectMarkov Chain Monte Carlopt_PT
dc.titleOn the use of finite mixtures to improve the physical interpretation of a ground vortex flowpt_PT
dc.typejournal article
dspace.entity.typePublication
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/5876/UID%2FEMS%2F50022%2F2013/PT
oaire.citation.endPage353pt_PT
oaire.citation.startPage344pt_PT
oaire.citation.volume85pt_PT
oaire.fundingStream5876
person.familyNameResende Rodrigues da Silva
person.familyNamePanão
person.familyNameMartins Barata
person.givenNameAndré
person.givenNameMiguel Rosa Oliveira
person.givenNameJorge Manuel
person.identifierJ-4185-2012
person.identifiertnDRoxYAAAAJ
person.identifierhFY_5JYAAAAJ&hl
person.identifier.ciencia-id8219-4B2B-E1C7
person.identifier.ciencia-id181F-16AE-4536
person.identifier.ciencia-idF611-BBCC-DAA8
person.identifier.orcid0000-0002-4901-7140
person.identifier.orcid0000-0001-9561-9268
person.identifier.orcid0000-0001-9014-5008
person.identifier.scopus-author-id11440407500
person.identifier.scopus-author-id8900941900
person.identifier.scopus-author-id11439470600
project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.nameFundação para a Ciência e a Tecnologia
rcaap.embargofctCopyright cedido à editora no momento da publicação.pt_PT
rcaap.rightsrestrictedAccesspt_PT
rcaap.typearticlept_PT
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