Drop impact entrapment of bubble rings

Handle URI:
http://hdl.handle.net/10754/334508
Title:
Drop impact entrapment of bubble rings
Authors:
Thoraval, M.-J.; Takehara, K.; Etoh, T.G.; Thoroddsen, Sigurdur T. ( 0000-0001-6997-4311 )
Abstract:
We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 -s after the first contact, requiring imaging at 1 million f.p.s. For a water drop impacting on a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Reynolds number Re above -12 000, up to 10 partial bubble rings have been observed at the base of the ejecta, starting when the contact is -20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into micro-bubbles. The different refractive index in the pool liquid reveals the destabilization of the vortices and the formation of streamwise vortices and intricate vortex tangles. Fine-scale axisymmetry is thereby destroyed. We show also that the shape of the drop has a strong influence on these dynamics. 2013 Cambridge University Press.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division
Citation:
Thoraval M-J, Takehara K, Etoh TG, Thoroddsen ST (2013) Drop impact entrapment of bubble rings. J Fluid Mech 724: 234-258. doi:10.1017/jfm.2013.147.
Publisher:
Cambridge University Press (CUP)
Journal:
Journal of Fluid Mechanics
Issue Date:
29-Apr-2013
DOI:
10.1017/jfm.2013.147
Type:
Article
ISSN:
00221120
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorThoraval, M.-J.en
dc.contributor.authorTakehara, K.en
dc.contributor.authorEtoh, T.G.en
dc.contributor.authorThoroddsen, Sigurdur T.en
dc.date.accessioned2014-11-11T14:27:41Z-
dc.date.available2014-11-11T14:27:41Z-
dc.date.issued2013-04-29en
dc.identifier.citationThoraval M-J, Takehara K, Etoh TG, Thoroddsen ST (2013) Drop impact entrapment of bubble rings. J Fluid Mech 724: 234-258. doi:10.1017/jfm.2013.147.en
dc.identifier.issn00221120en
dc.identifier.doi10.1017/jfm.2013.147en
dc.identifier.urihttp://hdl.handle.net/10754/334508en
dc.description.abstractWe use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 -s after the first contact, requiring imaging at 1 million f.p.s. For a water drop impacting on a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Reynolds number Re above -12 000, up to 10 partial bubble rings have been observed at the base of the ejecta, starting when the contact is -20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into micro-bubbles. The different refractive index in the pool liquid reveals the destabilization of the vortices and the formation of streamwise vortices and intricate vortex tangles. Fine-scale axisymmetry is thereby destroyed. We show also that the shape of the drop has a strong influence on these dynamics. 2013 Cambridge University Press.en
dc.language.isoenen
dc.publisherCambridge University Press (CUP)en
dc.rightshttp://creativecommons.org/licenses/by-nc-sa/3.0/en
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/3.0/en
dc.subjectbreakup/coalescenceen
dc.subjectdrops and bubblesen
dc.subjectAzimuthal instabilityen
dc.subjectBreakup/coalescenceen
dc.subjectDrops and bubblesen
dc.subjectHigh-impact velocitiesen
dc.subjectIsolated bubblesen
dc.subjectLow-impact velocityen
dc.subjectStreamwise vorticesen
dc.subjectUltra high speeden
dc.subjectLakesen
dc.subjectLiquidsen
dc.subjectRefractive indexen
dc.subjectReynolds numberen
dc.subjectVortex flowen
dc.subjectDropsen
dc.subjectbubbleen
dc.subjectcoalescenceen
dc.subjectdropleten
dc.subjectexperimental studyen
dc.subjectfluid dynamicsen
dc.subjectimpacten
dc.subjectnumerical modelen
dc.subjectrefractive indexen
dc.titleDrop impact entrapment of bubble ringsen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalJournal of Fluid Mechanicsen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, Kinki University, Higashi-Osaka 577-8502, Japanen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorThoraval, Marie-Jeanen
kaust.authorThoroddsen, Sigurdur T.en
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