imported>CycoMa2 at 15:17, 26 October 2021

2021-10-26T15:17:20Z

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{{No footnotes|date=October 2021}}

'''Atkinson friction factor''' is a measure of the resistance to airflow of a duct. It is widely used in the [[Underground mine ventilation|mine ventilation]] industry but is rarely referred to outside of it.

Atkinson friction factor is represented by the symbol <math>k</math> and has the same units as air density (kilograms per cubic metre in [[SI|SI units]], lbfmin^2/ft^4 in [[Imperial unit]]s). It is related to the more widespread [[Fanning friction factor]] by

<math>
k = \frac{1}{2}\rho f,
</math>

in which <math>\rho</math> is the [[density of air]] in the shaft or roadway under consideration and <math>f</math> is Fanning friction factor (dimensionless). It is related to the [[Darcy friction factor]] by

<math>
k = \frac{1}{2}\rho \frac{\lambda}{4},
</math>

in which <math>\lambda</math> is the Darcy friction factor (dimensionless).

It was introduced by John J Atkinson in an early mathematical treatment of mine ventilation (1862) and has been known under his name ever since.

==See also==

* [[Atkinson resistance]]

==References==

* NCB Mining Dept., ''Ventilation in coal mines: a handbook for colliery ventilation officers,'' National Coal Board 1979.

==Further reading==
* [https://www.mvsengineering.com/files/Publications/08th_US-1.pdf 1999 paper giving the derivation of <math>k</math>]
* Atkinson, J J, ''Gases met with in Coal Mines, and the general principles of Ventilation'' Transactions of the Manchester Geological Society, Vol. III, p.218, 1862

[[Category:Fluid dynamics]]
[[Category:Mine ventilation]]

Atkinson friction factor - Revision history

imported>CycoMa2 at 15:17, 26 October 2021