Openfoam friction coefficient differences.
I am investigating a pipe flow which has the following dimensions.
Length 30m, diameter 0.1. A uniform inlet velocity of 10m/s was used as a boundary with a pressure oulet of 0Pa.
I checked the Yplus.
The pressure at the inlet is 285Pa
dp/dx is -9.433.
With the following formule i calculated the friction coefficient:
dp/dx=(-0.5 x rho x 10² x cf) /D
cf=0.0154 or something like that. And I would like to have a friction factor of 0.019.
Because that is the friction factor that I should have if I fill in my Re, for a smooth pipe situation. I looked this up in a applied fluid dynamic handbook, there is a graph with the friction coefficient vs reynolds number.
Anybody has an idea of an increase in pressure, so that my dp/dx becomes 11.7 and therefore my friction factor 1.9?
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