Fanning Friction Factor for Smooth and Rough Pipes

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This Demonstration plots the Fanning friction factor versus the Reynolds number, , for both rough and smooth pipes.


The Fanning friction factor is given by the following relationships:

(i) For a laminar regime (,


(ii) for a turbulent regime in smooth pipes (,

(Blasius equation),

(iii) for a turbulent regime in rough pipes (,

(Colebrook–White equation),

where is the roughness ratio. The light green shaded region corresponds to the laminar/turbulent transition regime where experimental results are unreliable.

Side note: an explicit version of the Colebrook–White equation derived by Shacham (see [1])

gives equivalent results.


Contributed by: Housam Binous and Brian G. Higgins (September 2011)
Open content licensed under CC BY-NC-SA




[1] J. O. Wilkes, Fluid Mechanics for Chemical Engineers, Upper Saddle River, NJ: Prentice Hall, 1999.

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