Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water

Handle URI:
http://hdl.handle.net/10754/563225
Title:
Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water
Authors:
Vakarelski, Ivan Uriev ( 0000-0001-9244-9160 ) ; Chan, Derek Y C; Thoroddsen, Sigurdur T. ( 0000-0001-6997-4311 )
Abstract:
We investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 104 and 106, spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies. © the Partner Organisations 2014.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; High-Speed Fluids Imaging Laboratory
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Soft Matter
Issue Date:
2014
DOI:
10.1039/c4sm00368c
Type:
Article
ISSN:
1744683X
Sponsors:
We acknowledge G. D. Li from the KAUST Solar and Photovoltaics Research Center for assisting in the water tank and heater device design, and the KAUST Machine Workshop for the support in setting the experiments. This work is support in part by an Australian Research Council Discovery Project Grant to DYCC.
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.authorVakarelski, Ivan Urieven
dc.contributor.authorChan, Derek Y Cen
dc.contributor.authorThoroddsen, Sigurdur T.en
dc.date.accessioned2015-08-03T11:43:34Zen
dc.date.available2015-08-03T11:43:34Zen
dc.date.issued2014en
dc.identifier.issn1744683Xen
dc.identifier.doi10.1039/c4sm00368cen
dc.identifier.urihttp://hdl.handle.net/10754/563225en
dc.description.abstractWe investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 104 and 106, spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies. © the Partner Organisations 2014.en
dc.description.sponsorshipWe acknowledge G. D. Li from the KAUST Solar and Photovoltaics Research Center for assisting in the water tank and heater device design, and the KAUST Machine Workshop for the support in setting the experiments. This work is support in part by an Australian Research Council Discovery Project Grant to DYCC.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.titleLeidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in wateren
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentHigh-Speed Fluids Imaging Laboratoryen
dc.identifier.journalSoft Matteren
dc.contributor.institutionDepartment of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australiaen
dc.contributor.institutionDepartment of Chemistry and Biotechnology, Swinburne University of Technology, Hawthorn, VIC 3122, Australiaen
kaust.authorVakarelski, Ivan Urieven
kaust.authorThoroddsen, Sigurdur T.en
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.