Fanning Friction Factor for Smooth and Rough Pipes

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.


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