[kevinpwp]

Hi,

Suppose we have a factory that has two big doors and a lot of windows at top of the walls.
One door is on the north wall and the other door is on the west wall. Both doors are always open.

As the wind flow direction is north to the south, we know that the flow enters from the north door.

Also we assume that the windows are outlets which I think is a good assumption.

But the problem is that we don't know that the flow enters from the west door (Inlet) or exits (Outlet).

What should I do with the west door boundary condition?

I use ANSYS FLUENT.

Thanks.

[LuckyTran]

You can use either a pressure inlet or outlet. The differences between them are:

Pressure inlet imposes stagnation conditions for inflows.
Pressure outlet imposes static pressure at the boundary for outflow and static properties for inflow.

You choose inlet or outlet based on the convenient of the properties you have at hand. You will get reverse flow warnings when an inlet has outflow and when an outlet has inflow, but they can be safely ignored.

[JBeilke]

Place your boundaries outside of your building and also simulate the flow around the building.

[kevinpwp]

Originally Posted by LuckyTran

You can use either a pressure inlet or outlet. The differences between them are:

Pressure inlet imposes stagnation conditions for inflows.
Pressure outlet imposes static pressure at the boundary for outflow and static properties for inflow.

You choose inlet or outlet based on the convenient of the properties you have at hand. You will get reverse flow warnings when an inlet has outflow and when an outlet has inflow, but they can be safely ignored.

The reverse flow is important for me cause I wanna check which door (or windows) do not work very well so I install some fans , etc. there to move the air outside the building.
So, can I count on the reverse flow results? I mean where I get reverse flow warning, does it mean there is really a reverse flow and the reverse flow results are OK and accurate?

Thank you.

Originally Posted by JBeilke

Place your boundaries outside of your building and also simulate the flow around the building.

Thanks for your reply, but that makes the domain very wide and needs more computational resources.

[LuckyTran]

You can do the test yourself with flow in a pipe. Use a pressure inlet at an outlet and watch what happens. Also use a pressure outlet at an inlet and watch what happens. Comment on the accuracy of the results. I give you homework.