Friction velocity: Difference between revisions
From Glossary of Meteorology
No edit summary |
m (Rewrite with Template:Term and clean up) |
||
| Line 1: | Line 1: | ||
{{Term | |||
|Display title=friction velocity | |||
{{ | |Definitions={{Definition | ||
{{ | |Num=1 | ||
|Meaning= | |||
A reference [[wind]] velocity defined by the relation <blockquote>[[File:ams2001glos-Fe17.gif|link=|center|ams2001glos-Fe17]]</blockquote> where τ is the [[Reynolds stresses|Reynolds stress]], ρ the [[density]], and ''u''<sub>*</sub> friction velocity.<br/> Using the surface kinematic [[momentum]] fluxes in the ''x'' and ''y'' directions ([[File:ams2001glos-Fex10.gif|link=|ams2001glos-Fex10]]) to represent surface [[stress]], the friction velocity can be written as <blockquote>[[File:ams2001glos-Fe18.gif|link=|center|ams2001glos-Fe18]]</blockquote> It is usually applied to motion near the ground where the [[shearing stress]] is often assumed to be independent of height and approximately proportional to the square of the [[mean velocity]]. The friction velocity is, therefore, exactly the [[velocity]] for which this square law would be valid.<br/> Sutton, O. G. 1953. Micrometeorology. p. 76. | |||
}} | |||
}} | |||
Latest revision as of 12:10, 30 March 2024
A reference wind velocity defined by the relation
Using the surface kinematic momentum fluxes in the x and y directions (
) to represent surface stress, the friction velocity can be written as
Sutton, O. G. 1953. Micrometeorology. p. 76.
where τ is the Reynolds stress, ρ the density, and u* friction velocity.
Using the surface kinematic momentum fluxes in the x and y directions (
) to represent surface stress, the friction velocity can be written as It is usually applied to motion near the ground where the shearing stress is often assumed to be independent of height and approximately proportional to the square of the mean velocity. The friction velocity is, therefore, exactly the velocity for which this square law would be valid.
Sutton, O. G. 1953. Micrometeorology. p. 76.
