Vortex-induced buckling of a viscous drop impacting a pool

Handle URI:
http://hdl.handle.net/10754/625266
Title:
Vortex-induced buckling of a viscous drop impacting a pool
Authors:
Li, Erqiang ( 0000-0002-5003-0756 ) ; Beilharz, Daniel; Thoroddsen, Sigurdur T. ( 0000-0001-6997-4311 )
Abstract:
We study the intricate buckling patterns which can form when a viscous drop impacts a much lower viscosity miscible pool. The drop enters the pool by its impact inertia, flattens, and sinks by its own weight while stretching into a hemispheric bowl. Upward motion along the outer bottom surface of this bowl produces a vortical boundary layer which separates along its top and rolls up into a vortex ring. The vorticity is therefore produced in a fundamentally different way than for a drop impacting a pool of the same liquid. The vortex ring subsequently advects into the bowl, thereby stretching the drop liquid into ever thinner sheets, reaching the micron level. The rotating motion around the vortex pulls in folds to form multiple windings of double-walled toroidal viscous sheets. The axisymmetric velocity field thereby stretches the drop liquid into progressively finer sheets, which are susceptible to both axial and azimuthal compression-induced buckling. The azimuthal buckling of the sheets tends to occur on the inner side of the vortex ring, while their folds can be stretched and straightened on the outside edge. We characterize the total stretching from high-speed video imaging and use particle image velocimetry to track the formation and evolution of the vortex ring. The total interfacial area between the drop and the pool liquid can grow over 40-fold during the first 50 ms after impact. Increasing pool viscosity shows entrapment of a large bubble on top of the drop, while lowering the drop viscosity produces intricate buckled shapes, appearing at the earliest stage and being promoted by the crater motions. We also present an image collage of the most intriguing and convoluted structures observed. Finally, a simple point-vortex model reproduces some features from the experiments and shows variable stretching along the wrapping sheets.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division
Citation:
Li EQ, Beilharz D, Thoroddsen ST (2017) Vortex-induced buckling of a viscous drop impacting a pool. Physical Review Fluids 2. Available: http://dx.doi.org/10.1103/physrevfluids.2.073602.
Publisher:
American Physical Society (APS)
Journal:
Physical Review Fluids
Issue Date:
20-Jul-2017
DOI:
10.1103/physrevfluids.2.073602
Type:
Article
ISSN:
2469-990X
Sponsors:
The work described herein was supported by King Abdullah University of Science and Technology (KAUST) research funding (URF/1/2621-01-01). Some of the videos in the Supplemental Material were submitted to the Gallery of Fluid Motions of the APS-DFD meeting held in Boston in November 2015. Li is grateful for the Thousand Young Talents Program of China, the National Natural Science Foundation of China (Grant No. 11621202), and the Fundamental Research Funds for the Central Universities (Grant No. WK2090050041). Beilharz was an intern at KAUST during the early phase of this work. We thank Joachim Delannoy for a helpful discussion on the modeling.
Additional Links:
https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.2.073602
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorLi, Erqiangen
dc.contributor.authorBeilharz, Danielen
dc.contributor.authorThoroddsen, Sigurdur T.en
dc.date.accessioned2017-07-26T06:19:11Z-
dc.date.available2017-07-26T06:19:11Z-
dc.date.issued2017-07-20en
dc.identifier.citationLi EQ, Beilharz D, Thoroddsen ST (2017) Vortex-induced buckling of a viscous drop impacting a pool. Physical Review Fluids 2. Available: http://dx.doi.org/10.1103/physrevfluids.2.073602.en
dc.identifier.issn2469-990Xen
dc.identifier.doi10.1103/physrevfluids.2.073602en
dc.identifier.urihttp://hdl.handle.net/10754/625266-
dc.description.abstractWe study the intricate buckling patterns which can form when a viscous drop impacts a much lower viscosity miscible pool. The drop enters the pool by its impact inertia, flattens, and sinks by its own weight while stretching into a hemispheric bowl. Upward motion along the outer bottom surface of this bowl produces a vortical boundary layer which separates along its top and rolls up into a vortex ring. The vorticity is therefore produced in a fundamentally different way than for a drop impacting a pool of the same liquid. The vortex ring subsequently advects into the bowl, thereby stretching the drop liquid into ever thinner sheets, reaching the micron level. The rotating motion around the vortex pulls in folds to form multiple windings of double-walled toroidal viscous sheets. The axisymmetric velocity field thereby stretches the drop liquid into progressively finer sheets, which are susceptible to both axial and azimuthal compression-induced buckling. The azimuthal buckling of the sheets tends to occur on the inner side of the vortex ring, while their folds can be stretched and straightened on the outside edge. We characterize the total stretching from high-speed video imaging and use particle image velocimetry to track the formation and evolution of the vortex ring. The total interfacial area between the drop and the pool liquid can grow over 40-fold during the first 50 ms after impact. Increasing pool viscosity shows entrapment of a large bubble on top of the drop, while lowering the drop viscosity produces intricate buckled shapes, appearing at the earliest stage and being promoted by the crater motions. We also present an image collage of the most intriguing and convoluted structures observed. Finally, a simple point-vortex model reproduces some features from the experiments and shows variable stretching along the wrapping sheets.en
dc.description.sponsorshipThe work described herein was supported by King Abdullah University of Science and Technology (KAUST) research funding (URF/1/2621-01-01). Some of the videos in the Supplemental Material were submitted to the Gallery of Fluid Motions of the APS-DFD meeting held in Boston in November 2015. Li is grateful for the Thousand Young Talents Program of China, the National Natural Science Foundation of China (Grant No. 11621202), and the Fundamental Research Funds for the Central Universities (Grant No. WK2090050041). Beilharz was an intern at KAUST during the early phase of this work. We thank Joachim Delannoy for a helpful discussion on the modeling.en
dc.publisherAmerican Physical Society (APS)en
dc.relation.urlhttps://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.2.073602en
dc.rightsArchived with thanks to Physical Review Fluidsen
dc.titleVortex-induced buckling of a viscous drop impacting a poolen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalPhysical Review Fluidsen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Modern Mechanics, University of Science and Technology of China, Hefei 230027, Chinaen
dc.contributor.institutionLadHyX, École polytechnique, 91128 Palaiseau and PMMH, ESPCI Paris, 75005 Paris, Franceen
kaust.authorLi, Erqiangen
kaust.authorThoroddsen, Sigurdur T.en
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