Bubble entrapment during sphere impact onto quiescent liquid surfaces

Handle URI:
http://hdl.handle.net/10754/561802
Title:
Bubble entrapment during sphere impact onto quiescent liquid surfaces
Authors:
Marston, Jeremy; Vakarelski, Ivan Uriev ( 0000-0001-9244-9160 ) ; Thoroddsen, Sigurdur T. ( 0000-0001-6997-4311 )
Abstract:
We report observations of air bubble entrapment when a solid sphere impacts a quiescent liquid surface. Using high-speed imaging, we show that a small amount of air is entrapped at the bottom tip of the impacting sphere. This phenomenon is examined across a broad range of impact Reynolds numbers, 0.2 a Re = (DU0/Il) a 1.2' 105. Initially, a thin air pocket is formed due to the lubrication pressure in the air layer between the sphere and the liquid surface. As the liquid surface deforms, the liquid contacts the sphere at a finite radius, producing a thin sheet of air which usually contracts to a nearly hemispherical bubble at the bottom tip of the sphere depending on the impact parameters and liquid properties. When a bubble is formed, the final bubble size increases slightly with the sphere diameter, decreases with impact speed but appears independent of liquid viscosity. In contrast, for the largest viscosities tested herein, the entrapped air remains in the form of a sheet, which subsequently deforms upon close approach to the base of the tank. The initial contact diameter is found to conform to scalings based on the gas Reynolds number whilst the initial thickness of the air pocket or adimplea scales with a Stokes' number incorporating the influence of the air viscosity, sphere diameter and impact speed and liquid density. © 2011 Cambridge University Press.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Clean Combustion Research Center; Mechanical Engineering Program; High-Speed Fluids Imaging Laboratory
Publisher:
Cambridge University Press (CUP)
Journal:
Journal of Fluid Mechanics
Issue Date:
20-Jun-2011
DOI:
10.1017/jfm.2011.202
Type:
Article
ISSN:
00221120
Sponsors:
This work was partially supported by KAUST AEA grant 7000000028.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorMarston, Jeremyen
dc.contributor.authorVakarelski, Ivan Urieven
dc.contributor.authorThoroddsen, Sigurdur T.en
dc.date.accessioned2015-08-03T09:04:56Zen
dc.date.available2015-08-03T09:04:56Zen
dc.date.issued2011-06-20en
dc.identifier.issn00221120en
dc.identifier.doi10.1017/jfm.2011.202en
dc.identifier.urihttp://hdl.handle.net/10754/561802en
dc.description.abstractWe report observations of air bubble entrapment when a solid sphere impacts a quiescent liquid surface. Using high-speed imaging, we show that a small amount of air is entrapped at the bottom tip of the impacting sphere. This phenomenon is examined across a broad range of impact Reynolds numbers, 0.2 a Re = (DU0/Il) a 1.2' 105. Initially, a thin air pocket is formed due to the lubrication pressure in the air layer between the sphere and the liquid surface. As the liquid surface deforms, the liquid contacts the sphere at a finite radius, producing a thin sheet of air which usually contracts to a nearly hemispherical bubble at the bottom tip of the sphere depending on the impact parameters and liquid properties. When a bubble is formed, the final bubble size increases slightly with the sphere diameter, decreases with impact speed but appears independent of liquid viscosity. In contrast, for the largest viscosities tested herein, the entrapped air remains in the form of a sheet, which subsequently deforms upon close approach to the base of the tank. The initial contact diameter is found to conform to scalings based on the gas Reynolds number whilst the initial thickness of the air pocket or adimplea scales with a Stokes' number incorporating the influence of the air viscosity, sphere diameter and impact speed and liquid density. © 2011 Cambridge University Press.en
dc.description.sponsorshipThis work was partially supported by KAUST AEA grant 7000000028.en
dc.publisherCambridge University Press (CUP)en
dc.subjectbubble dynamicsen
dc.subjectcontact linesen
dc.subjectlubrication theoryen
dc.titleBubble entrapment during sphere impact onto quiescent liquid surfacesen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentHigh-Speed Fluids Imaging Laboratoryen
dc.identifier.journalJournal of Fluid Mechanicsen
kaust.authorMarston, Jeremyen
kaust.authorVakarelski, Ivan Urieven
kaust.authorThoroddsen, Sigurdur T.en
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