Editing Bubble ring (section)

{{Short description|Toroidal vortex ring of air in water}}
{{for|the bubble-blowing toy|Soap bubble#Use in play}}
[[File:Bubble Ring in Sunlight (cropped).jpg|thumb|upright=1.3|{{center|Bubble ring}}]]

A '''bubble ring''', or '''toroidal bubble''', is an underwater [[vortex ring]] where an air bubble occupies the core of the vortex, forming a ring shape. The ring of air as well as the nearby water spins [[Toroidal and poloidal|poloidally]] as it travels through the water, much like a flexible bracelet might spin when it is rolled on to a person's arm. The faster the bubble ring spins, the more stable it becomes.<ref>{{cite journal | last1 = Yoona | first1 = SS | last2 = Heister | first2 = SD  |author2-link=Stephen Douglas Heister | year = 2004 | title = A nonlinear atomization model based on a boundary layer instability mechanism | url = http://solarcellaerosol.korea.ac.kr/papers/paper-journal/ssyoon5_BLI_PoF2004.pdf | journal = Physics of Fluids | volume = 16 | issue = 1 | pages = 47–61 | doi = 10.1063/1.1629301 | bibcode = 2004PhFl...16...47Y | access-date = 2010-05-23 | archive-url = https://web.archive.org/web/20110722132615/http://solarcellaerosol.korea.ac.kr/papers/paper-journal/ssyoon5_BLI_PoF2004.pdf | archive-date = 2011-07-22 | url-status = dead }}</ref> The physics of vortex rings are still under active study in [[fluid dynamics]].<ref>{{cite journal | last1 = Ruban | first1 = VP | last2 = Rasmussen | first2 = JJ | year = 2003 | title = Toroidal bubbles with circulation in ideal hydrodynamics: A variational approach | journal = Phys. Rev. | volume = 68 | issue = 5| page = 5 | doi=10.1103/PhysRevE.68.056301| pmid = 14682878 |arxiv = physics/0306029 |bibcode = 2003PhRvE..68e6301R | s2cid = 11765709 }}</ref><ref>{{cite journal | last1 = Wang | first1 = QX | last2 = Yeo | first2 = KS | last3 = Khoo | first3 = BC | last4 = Lam | first4 = KY | year = 2005 | title = VORTEX ring modelling of toroidal bubbles | url = http://web.mat.bham.ac.uk/Q.X.Wang/papers_pdf/toroidal_bubble_wqx.pdf | journal = Theoretical and Computational Fluid Dynamics | volume = 19 | issue = 5| pages = 1432–2250 | doi=10.1007/s00162-005-0164-6|bibcode = 2005ThCFD..19..303W | s2cid = 52219528 }}</ref> Devices have been invented which generate bubble vortex rings.<ref>United States Patent: [http://www.google.co.nz/patents?hl=en&lr=&vid=USPAT7300040&id=O-KcAAAAEBAJ&oi=fnd&dq=%22ring+bubbles%22&printsec=abstract#v=onepage&q&f=false Simple method for the controlled production of VORTEX ring bubbles of a gas] {{Webarchive|url=https://web.archive.org/web/20110926205326/http://www.google.co.nz/patents?hl=en&lr=&vid=USPAT7300040&id=O-KcAAAAEBAJ&oi=fnd&dq=%22ring+bubbles%22&printsec=abstract#v=onepage&q&f=false |date=2011-09-26 }} Issued patent: 6824125, 30 November 2004.</ref><ref>United States Patent: [http://www.google.co.nz/patents?id=O-KcAAAAEBAJ&printsec=description&zoom=4#v=onepage&q&f=false Simple, mechanism-free device, and method to produce VORTEX ring bubbles in liquids] {{Webarchive|url=https://web.archive.org/web/20120224202432/http://www.google.co.nz/patents?id=O-KcAAAAEBAJ&printsec=description&zoom=4#v=onepage&q&f=false |date=2012-02-24 }} Patent number: 7300040. 27 November 2007.</ref>