Reynolds number: Difference between revisions
From Glossary of Meteorology
imported>Perlwikibot (Created page with " {{TermHeader}} {{TermSearch}} <div class="termentry"> <div class="term"> == Reynolds number == </div> <div class="definition"><div class="short_definition">The dimensi...") |
imported>Perlwikibot No edit summary |
||
| Line 9: | Line 9: | ||
</div> | </div> | ||
<div class="definition"><div class="short_definition">The dimensionless ratio of the [[inertial force]] (∼''U''<sup>2</sup>/''L'') to the [[viscous force]] (∼ ν''U''/''L''<sup>2</sup>) in the [[Navier–Stokes equations]], where ''U'' is a [[characteristic velocity]], ''L'' is a [[characteristic length]], and ν is the [[kinematic viscosity]] of the fluid; thus, <div class="display-formula"><blockquote>[[File:ams2001glos-Re39.gif|link=|center|ams2001glos-Re39]]</blockquote></div></div><br/><div class="paragraph">The Reynolds number is of great importance in the theory of [[hydrodynamic stability]] and the origin of [[turbulence]]. The inertia force generates [[vortex stretching]] and [[nonlinear]] interactions and hence creates [[randomness]]. Turbulence occurs when the inertia term dominates the viscous term, that is, when the Reynolds number is large. For many engineering flows, turbulence occurs when Re > Re<sub>c</sub>, where the critical Reynolds number is roughly Re<sub>c</sub> = 2100. <br/>''See'' [[large Reynolds number flow]].</div><br/> </div> | <div class="definition"><div class="short_definition">The dimensionless ratio of the [[inertial force]] (∼''U''<sup>2</sup>/''L'') to the [[viscous force]] (∼ ν''U''/''L''<sup>2</sup>) in the [[Navier–Stokes equations]], where ''U'' is a [[characteristic velocity]], ''L'' is a [[characteristic length]], and ν is the [[kinematic viscosity|kinematic viscosity]] of the fluid; thus, <div class="display-formula"><blockquote>[[File:ams2001glos-Re39.gif|link=|center|ams2001glos-Re39]]</blockquote></div></div><br/><div class="paragraph">The Reynolds number is of great importance in the theory of [[hydrodynamic stability]] and the origin of [[turbulence]]. The inertia force generates [[vortex stretching]] and [[nonlinear]] interactions and hence creates [[randomness]]. Turbulence occurs when the inertia term dominates the viscous term, that is, when the Reynolds number is large. For many engineering flows, turbulence occurs when Re > Re<sub>c</sub>, where the critical Reynolds number is roughly Re<sub>c</sub> = 2100. <br/>''See'' [[large Reynolds number flow|large Reynolds number flow]].</div><br/> </div> | ||
</div> | </div> | ||
Latest revision as of 16:47, 25 April 2012
Reynolds number
The dimensionless ratio of the inertial force (∼U2/L) to the viscous force (∼ νU/L2) in the Navier–Stokes equations, where U is a characteristic velocity, L is a characteristic length, and ν is the kinematic viscosity of the fluid; thus,
The Reynolds number is of great importance in the theory of hydrodynamic stability and the origin of turbulence. The inertia force generates vortex stretching and nonlinear interactions and hence creates randomness. Turbulence occurs when the inertia term dominates the viscous term, that is, when the Reynolds number is large. For many engineering flows, turbulence occurs when Re > Rec, where the critical Reynolds number is roughly Rec = 2100.
See large Reynolds number flow.
See large Reynolds number flow.
