Reynolds number dependence of mean flow structure in square duct turbulence

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dc.contributor.authorPinelli, Alfredo
dc.contributor.authorUhlmann, Markus
dc.contributor.authorSekimoto, Atshushi
dc.contributor.authorKawahara, Genta
dc.date.accessioned2023-06-20T03:33:31Z
dc.date.available2023-06-20T03:33:31Z
dc.date.issued2010
dc.description.abstractWe have performed direct numerical simulations of turbulent flows in a square duct considering a range of Reynolds numbers spanning from a marginal state up to fully developed turbulent states at low Reynolds numbers. The main motivation stems from the relatively poor knowledge about the basic physical mechanisms that are responsible for one of the most outstanding features of this class of turbulent flows: Prandtl's secondary motion of the second kind. In particular, the focus is upon the role of flow structures in its generation and characterization when increasing the Reynolds number. We present a two-fold scenario. On the one hand, buffer layer structures determine the distribution of mean streamwise vorticity. On the other hand, the shape and the quantitative character of the mean secondary flow, defined through the mean cross-stream function, are influenced by motions taking place at larger scales. It is shown that high velocity streaks are preferentially located in the corner region (e.g. less than 50 wall units apart from a sidewall), flanked by low velocity ones. These locations are determined by the positioning of quasi-streamwise vortices with a preferential sign of rotation in agreement with the above described velocity streaks' positions. This preferential arrangement of the classical buffer layer structures determines the pattern of the mean streamwise vorticity that approaches the corners with increasing Reynolds number. On the other hand, the centre of the mean secondary flow, defined as the position of the extrema of the mean cross-stream function (computed using the mean streamwise vorticity), remains at a constant location departing from the mean streamwise vorticity field for larger Reynolds numbers, i.e. it scales in outer units. This paper also presents a detailed validation of the numerical technique including a comparison of the numerical results with data obtained from a companion experiment.
dc.description.departmentDepto. de Análisis Matemático y Matemática Aplicada
dc.description.facultyFac. de Ciencias Matemáticas
dc.description.refereedTRUE
dc.description.sponsorshipExcellence for Research and Education on Complex Functional Mechanical Systems (COE program of the Ministry of Education, Culture, Sport, Science, and Technology of Japan)
dc.description.sponsorshipMinistry of Education and Science
dc.description.sponsorshipJapanese Society for the Promotion of Science
dc.description.statuspub
dc.eprint.idhttps://eprints.ucm.es/id/eprint/21887
dc.identifier.doi10.1017/S0022112009992242
dc.identifier.issn0022-1120
dc.identifier.officialurlhttp://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7243960&fulltextType=RA&fileId=S0022112009992242
dc.identifier.relatedurlhttp://www.cambridgejournals.org/
dc.identifier.urihttps://hdl.handle.net/20.500.14352/43867
dc.journal.titleJournal of fluid mechanics
dc.page.final122
dc.page.initial107
dc.publisherCambridge University Press
dc.relation.projectIDDPI-2002-040550-C07-04
dc.rights.accessRightsmetadata only access
dc.subject.cdu531
dc.subject.keywordNumerical-simulation
dc.subject.keywordsecondary flow
dc.subject.ucmFísica (Física)
dc.subject.unesco22 Física
dc.titleReynolds number dependence of mean flow structure in square duct turbulence
dc.typejournal article
dc.volume.number644
dspace.entity.typePublication
relation.isAuthorOfPublication2b7c93f7-c4d1-42d5-820a-333c428d96c2
relation.isAuthorOfPublication.latestForDiscovery2b7c93f7-c4d1-42d5-820a-333c428d96c2
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