operating pressure
 

Hi everyone!
I want to model laminar flow and heat transfer in a curved duct using Fluent. The B.Cs are: velocity inlet,4walls and outflow.Air has been selected as working fluid and the density changes based on incompressible ideal gas law which is an option for density in free convection problems and choosing operating pressure is very important in this formulation. Fluent offers that mean flow pressure should be used for operating pressure. But I don not know what is the mean flow pressure meaning and its value.
Thanks for your help

operating pressure is generally 1atm for external flows(101385 Pa or something very close), which is free air pressure at static conditions. I think it depends on your air characteristics inside duct, I mean temperature can change the static pressure of air.

Thanks for your reply. Is there a relation between operating pressure and air properties? I use default properties.