Fanning Friction Factor for Smooth and Rough Pipes
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.
f
F
Re
The Fanning friction factor is given by the following relationships:
(i) For a laminar regime (,
Re<2000)
f
F
16
Re
(ii) for a turbulent regime in smooth pipes (,
Re>4000)
f
F
-1/4
Re
(iii) for a turbulent regime in rough pipes (,
Re>4000)
1
f
F
ϵ
D
1.257
Re
f
F
where is the roughness ratio. The light green shaded region corresponds to the laminar/turbulent transition regime where experimental results are unreliable.
ϵ/D
Side note: an explicit version of the Colebrook–White equation derived by Shacham (see [1])
f
F
-2
ln0.269-ln0.269+
ϵ
D
2.185
Re
ϵ
D
14.5
Re
gives equivalent results.