Buoyancy driven flow

[Lukezo]

Hi people,

I'm about to model flow of air inside a vertical tube with air inlet at the bottom of tube about a feet away from bottom. The air gets moist and warm inside tube.

Can you ellaborate on boundary conditions?
2. Which is the appropriate outlet condition?

 

[3DDave]

How does the air become warm and moist in the tube?

 

[Lukezo]

By spraying hot water into air stream.

To simplify, plan is to implement udf connecting air velocity and temperature before moisturizing section.