main menu MyCT
Darcy friction factor

     Engineering index
Civil Engineering index
Darcy friction factor diagram
Serghide's solution to the Colebrook-White equation is used to approximate the Darcy friction factor within full flowing pipes with a Reynolds number (Re) above 4000. It tends to be very accurate to the iteratively determined Colebrook-White equation - within ~30 ppm accuracy.
Pipe diameter:
Roughness height (ε)
Reynolds number:

Darcy friction factor:
Add login to add

Note that the Darcy friction factor is directly related to the Fanning friction factor (which is 1/4 of the Darcy factor). In pure laminar flow, the Darcy factor can be taken as 64/Re (Reynolds number), but when the Reynolds number is above ~2300, turbulent flow means that an approach such as the Colebrook equation must be used.