Hello everybody,

I made a modelisation with the following parameters and i try to get the the skin friction factor in the lenght of the pipe this for different roughness.

3D inlet 0.015 m/s D= 1m L=20m water -> Re=15 000 symmetry pipe divided into two part.

Trying different times with :

Solver K-epsilon:

Ks=5e-5 -> Cf=1.5e-3 f=4*Cf=6e-3 Ks=2e-2 idem same value for Cf

I mean that the cavities of the roughness has an average diameter equal to 5e-5 m or 2e-2m.

whereas i expect according MOODY diagramme f=1.8e-3

I try with omega model i get a different Cf but still similar for the model.

I make maybe a misunderstanding with Ks;

If somebody would have a suggestion i would be very helpful.

BB

You can make an equivalence with the Nukeradse`s roughness and the Fluent parameters of roughness (roughness height and roughness constant). Chouaib

THANK YOU SORRY FOR BEING SO LATE