Empirical implicit correlation for Darcy friction factor f in non-smooth pipelines \epsilon > 0 which works for non-laminar ( {\rm Re} > 2,000) flow:
(1) | \frac{1}{\sqrt{f}} = -2 \, \log \left( \frac{\epsilon}{3.7 \, d} + \frac{2.51}{{\rm Re} \sqrt{f}} \right) |
where
{\rm Re} | Reynolds number of a pipe flow |
d | Inner diameter of a pipe |
\epsilon | inner pipe walls roughness |
See also
Physics / Fluid Dynamics / Pipe Flow Dynamics / Darcy–Weisbach equation / Darcy friction factor / Darcy friction factor @model