# Atkinson friction factor

Atkinson friction factor

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

Atkinson friction factor is represented by the symbol $k$ and has the same units as air density (kilograms per cubic metre in SI units, pounds per cubic foot in Imperial units). It is related to the more widespread Fanning friction factor by

$k = frac\left\{1\right\}\left\{2\right\} ho f,$

in which $ho$ is the density of air in the shaft or roadway under consideration and $f$ is Fanning friction factor (dimensionless). It is related to the Darcy friction factor by

$k = frac\left\{1\right\}\left\{2\right\} ho frac\left\{lambda\right\}\left\{4\right\},$

in which $lambda$ 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.

ee also

* Atkinson resistance

References

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

* [http://www.mvsengineering.com/admin/images/pdfs/Practical_Values_of_Friction_Factors.pdf 1999 paper giving the derivation of $k$]
* 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

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Friction factor — can refer to:* Darcy friction factor * Fanning friction factor * Atkinson friction factor (ventilation of mines) See also *coefficient of friction …   Wikipedia

• Atkinson resistance — is commonly used in mine ventilation to characterise the resistance to airflow of a duct of irregular size and shape, such as a mine roadway. It has the symbol R and is used in the square law for pressure drop,:Delta P = frac{ ho {actual{ ho… …   Wikipedia

• Frictional pressure drop — The frictional pressure drop is the decrease in pressure as a fluid passes through a conduit, caused by frictional losses within the conduit.This article was created to discuss merging the following articles: *Friction factor *Darcy friction… …   Wikipedia

• United Kingdom — a kingdom in NW Europe, consisting of Great Britain and Northern Ireland: formerly comprising Great Britain and Ireland 1801 1922. 58,610,182; 94,242 sq. mi. (244,100 sq. km). Cap.: London. Abbr.: U.K. Official name, United Kingdom of Great… …   Universalium

• literature — /lit euhr euh cheuhr, choor , li treuh /, n. 1. writings in which expression and form, in connection with ideas of permanent and universal interest, are characteristic or essential features, as poetry, novels, history, biography, and essays. 2.… …   Universalium

• Wind turbine design — An example of a wind turbine, this 3 bladed turbine is the classic design of modern wind turbines Wind turbines History Design …   Wikipedia

• Electric motor — For other kinds of motors, see motor (disambiguation). For a railroad electric engine, see electric locomotive. Various electric motors. A 9 volt PP3 transistor battery is in the center foreground for size comparison. An electric motor converts… …   Wikipedia

• Gulf War — This article is about the war in 1990/91. For other wars of that name, see Persian Gulf War (disambiguation). Operation Desert Storm redirects here. For the video game, see Operation: Desert Storm (video game). Gulf War …   Wikipedia

• Wind power — Wind power: worldwide installed capacity [1] …   Wikipedia

• Stirling engine — Alpha type Stirling engine. There are two cylinders. The expansion cylinder (red) is maintained at a high temperature while the compression cylinder (blue) is cooled. The passage between the two cylinders contains the regenerator …   Wikipedia