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visuja April 27, 2009 02:30

Outflow vs Pressure Outlet BCs

Could someone explain to me the difference between outflow and pressure outlet boundary conditions?

I simulated a steady state flow through a straight pipe using the two different boundary conditions at the outlet, with a velocity inlet boundary condition at the inlet. I get quite different results in terms of the total pressure drop. Why is this so?


Hertzel April 27, 2009 03:58

The conditions Fluent uses can be found in the manual

the outflow boundary condition is described in 7.10.1 and 7.10.2
the Pressure Outlet boundary is described in 7.8.1

taking a quick look at it i think the pressure outlet defines
-static pressure
-backflow condition
(and some other things)
while in the case of an outflow a zero diffusion flux is defined for all variables

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