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dc.contributor.authorVakarelski, Ivan Uriev
dc.contributor.authorKlaseboer, Evert
dc.contributor.authorJetly, Aditya
dc.contributor.authorMansoor, Mohammad M.
dc.contributor.authorAguirre-Pablo, Andres A.
dc.contributor.authorChan, Derek Y. C.
dc.contributor.authorThoroddsen, Sigurdur T
dc.date.accessioned2017-09-21T09:25:34Z
dc.date.available2017-09-21T09:25:34Z
dc.date.issued2017-09-09
dc.identifier.citationVakarelski IU, Klaseboer E, Jetly A, Mansoor MM, Aguirre-Pablo AA, et al. (2017) Self-determined shapes and velocities of giant near-zero drag gas cavities. Science Advances 3: e1701558. Available: http://dx.doi.org/10.1126/sciadv.1701558.
dc.identifier.issn2375-2548
dc.identifier.pmid28913434
dc.identifier.doi10.1126/sciadv.1701558
dc.identifier.urihttp://hdl.handle.net/10754/625505
dc.description.abstractMinimizing the retarding force on a solid moving in liquid is the canonical problem in the quest for energy saving by friction and drag reduction. For an ideal object that cannot sustain any shear stress on its surface, theory predicts that drag force will fall to zero as its speed becomes large. However, experimental verification of this prediction has been challenging. We report the construction of a class of self-determined streamlined structures with this free-slip surface, made up of a teardrop-shaped giant gas cavity that completely encloses a metal sphere. This stable gas cavity is formed around the sphere as it plunges at a sufficiently high speed into the liquid in a deep tank, provided that the sphere is either heated initially to above the Leidenfrost temperature of the liquid or rendered superhydrophobic in water at room temperature. These sphere-in-cavity structures have residual drag coefficients that are typically less than Embedded Image those of solid objects of the same dimensions, which indicates that they experienced very small drag forces. The self-determined shapes of the gas cavities are shown to be consistent with the Bernoulli equation of potential flow applied on the cavity surface. The cavity fall velocity is not arbitrary but is uniquely predicted by the sphere density and cavity volume, so larger cavities have higher characteristic velocities.
dc.description.sponsorshipThis work was supported by the King Abdullah University of Science and Technology. D.Y.C.C. was supported by the Australian Research Council through Discovery Project grant no. DP170100376.
dc.publisherAmerican Association for the Advancement of Science (AAAS)
dc.relation.urlhttp://advances.sciencemag.org/content/3/9/e1701558
dc.relation.urlhttp://advances.sciencemag.org/content/3/9/e1701558
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
dc.rights.urihttp://creativecommons.org/licenses/by-nc/4.0/
dc.titleSelf-determined shapes and velocities of giant near-zero drag gas cavities
dc.typeArticle
dc.contributor.departmentHigh-Speed Fluids Imaging Laboratory
dc.contributor.departmentMechanical Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalScience Advances
dc.eprint.versionPublisher's Version/PDF
dc.contributor.institutionInstitute of High Performance Computing, 1 Fusionopolis Way, Singapore 138632, Singapore.
dc.contributor.institutionDepartment of Mathematics, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
dc.contributor.institutionSchool of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010, Australia.
kaust.personVakarelski, Ivan Uriev
kaust.personJetly, Aditya
kaust.personMansoor, Mohammad M.
kaust.personAguirre-Pablo, Andres
kaust.personThoroddsen, Sigurdur T.
refterms.dateFOA2018-06-13T10:52:52Z


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This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
Except where otherwise noted, this item's license is described as This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.