Reynolds number, used to characterize the ï¬ow of viscous incompressible ï¬uids, was referred to as the most famous of the dimensionless numbers. In magnetohydrodynamics, the study of electrically conducting ï¬uids, another Reynolds number arises, the magnetic Reynolds number. It is deï¬ned as Rm = UL/η, where U and L are the characteristic velocity and length, and η is the magnetic diï¬usivity. It is often stated in the literature that the magnetic Reynolds number is a measure of the relative importance of magnetic convection to magnetic diï¬usion.1 That is not the case.2 Consider a conducting disk rotating between the poles of a magnet, as found in some residential electricity meters. Currents induced in the disk by the magnet distort the magnetic ï¬eld. The magnetic lines of force are dragged in the direction of rotation, but the disturbance is localized since the electrical conductivity is ï¬nite. The diï¬usion and convection processes must be equal in the steady state, irrespective of the value of the electrical conductivity of the disk and the value of the magnetic Reynolds number. This does not mean that the magnetic Reynolds number is meaningless; it is a measure of the distortion of the magnetic ï¬eld due
Analyses of dimensionless science
Abstract
Reynolds number, used to characterize the ï¬ow of viscous incompressible ï¬uids, was referred to as the most famous of the dimensionless numbers. In magnetohydrodynamics, the study of electrically conducting ï¬uids, another Reynolds number arises, the magnetic Reynolds number. It is deï¬ned as Rm = UL/η, where U and L are the characteristic velocity and length, and η is the magnetic diï¬usivity. It is often...End of preview. The entire article is 1 page. To view the full-text, please rent this article to continue.
/lp/american-institute-of-physics/analyses-of-dimensionless-science-wUFyb0RSSQ
Welcome to DeepDyve! Rent Premier Research Articles and Save Up to 90%
Analyses of dimensionless science
Blatter, Heinz
Follow Physics Today
, Volume 65 (2)
American Institute of Physics – Feb 1, 2012
More Info
More Like This Article
View All dataSource[]=actageo&dataSource[]=aspet&dataSource[]=aaos&dataSource[]=aacc&dataSource[]=aacr&dataSource[]=aea&dataSource[]=aip&dataSource[]=ajnr&dataSource[]=ams&dataSource[]=aps_physical&dataSource[]=appi_book&dataSource[]=appi_journal&dataSource[]=apha&dataSource[]=asip&dataSource[]=asm&dataSource[]=asn&dataSource[]=aspb&dataSource[]=avs&dataSource[]=annual_reviews&dataSource[]=arxiv&dataSource[]=acm&dataSource[]=berghahn&dataSource[]=cabi&dataSource[]=clinical_trials&dataSource[]=dailymed&dataSource[]=degruyter&dataSource[]=du_press&dataSource[]=esa&dataSource[]=eu_press&dataSource[]=elsevier&dataSource[]=emerald&dataSource[]=ejtr&dataSource[]=emea&dataSource[]=epo&dataSource[]=faseb&dataSource[]=gsa&dataSource[]=health_affairs&dataSource[]=hindawi&dataSource[]=imanager&dataSource[]=imedpub&dataSource[]=informa_healthcare&dataSource[]=informs&dataSource[]=iop&dataSource[]=iucr&dataSource[]=iospress&dataSource[]=jbjs&dataSource[]=leftcoast&dataSource[]=lu_press&dataSource[]=mesharpe&dataSource[]=mary_ann_liebert&dataSource[]=medline&dataSource[]=mit_press&dataSource[]=nature&dataSource[]=oxford&dataSource[]=pier_professional&dataSource[]=pnas&dataSource[]=portlandpress&dataSource[]=psyc_articles&dataSource[]=psyc_books&dataSource[]=psyc_critiques&dataSource[]=plos_journal&dataSource[]=pubmed_central&dataSource[]=rsna&dataSource[]=rockefeller&dataSource[]=rcn&dataSource[]=ria&dataSource[]=rsc&dataSource[]=sage&dataSource[]=spie&dataSource[]=springer_journal&dataSource[]=springer&dataSource[]=taylor_francis&dataSource[]=aps&dataSource[]=the_scientist&dataSource[]=uc_press&dataSource[]=uspto_abstract&dataSource[]=wiley&dataSource[]=pct
© 2012 DeepDyve, Inc. All rights reserved.
Terms of Service | Privacy Policy
