Turbulent flow in smooth rectangular duct - Numerical vs. Literature correlations
 

Hallo,

I have done simulations of a turbulent air flow in a smooth rectangular duct. I compared my numerical results of pressure drop (friction factor) with literature correlations.

Here follows a brief summary of my simulation (because of symmetry I have only simulated one-fourth of the duct):

Fluid: air with costant properties
Turb model: k-w standard
y+: everywhere below 2.5 and above 0.8
Inlet B.C.: mass flow inlet
Outlet B.C.: outflow
Reynolds number: 7666

I compared my results for the pressure drop (or friction factor) with some literature correlations, e.g. f=(1.82*log_10 Re -1.64)^-2 and I have found a mean discrepancy of 12%.

I have also performed a sensitivity analysis on the grid but the results do not change.

Can anyone inform me if such a discrepancy is acceptable or if it is typically possible to obtain a better agreement between numerical simulations and literature correlations for the friction factor (or pressure drop)?

Thank you in advance,
marluc