Exchange Coefficients

From ExoDictionary
Revision as of 16:00, 7 April 2007 by Autostub3 (Talk)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
This definition page has been automatically generated.
You can help ExoDictionary by expanding, updating, or correcting it.


This autostub has not yet had its initial copyediting proof and may contain significant formatting and even factual errors. You can improve Exodictionary by cleaning up the page markup and verifying that the definition is correct and then removing this tag.


This autostub has not yet had its initial categorization proof and may be categorized incorrectly. You can improve Exodictionary by removing inappropriate categories and then removing this tag.


Exchange Coefficients

</dt>
Coefficients of eddy flux (e.g., of momentum, heat, water vapor, etc.) in turbulent flow, defined in analogy to those of the kinetic theory of gases (see eddy). Also called austausch coefficients, eddy coefficients, interchange coefficients. </dd>
The exchange-coefficient hypothesis states that the mean eddy flux per unit area of a conservative quantity (suitability expressed) is proportional to the gradient of the mean value of this quantity, that is,

Mean flux per unit area = -Ce (dMissing Image:img src="SP7-e_files/Ebar.gif"/ dN)
where Ce is the exchange

coefficient; E is the mean value of the quantity; and N is the direction normal to the surface. In strict analogy to molecular properties; Ce would be constant, for turbulent flow Ce turns out to depend on time and location. See eddy viscosity diffusivity. [[/a>|/a> ]]

References

This article is based on NASA's Dictionary of Technical Terms for Aerospace Use