[Taataa]

I am trying to model a Taylor bubble using interFoam. The setup is very simple, just a box (1x10 cm) and all the boundaries are wall and the whole domain is filled with water.

The case is similar to this

When I admit a Taylor bubble (almost occupies the width of the column except for thin film) at the bottom of the domain, the bubble rises as long as it doesn't occupy the whole section. When it does, it just stays there and basically the domain will be divided into three section water at the top of air then only air section then water below it.

Can anyone explain what's happening (wrong)?

[piu58]

I assume you simulate the gravity driven, ascending gas in a closed tube.

You have a no slip boundary conditions. If the bubble occupies the whole diameter the downward flow of the liquid stops. This is correct for microflows, where tiny bubbles block the diameter.

To get to a more realistic model I recommend to include the wetting of the pipe in your model / b.c. Therewith you have at least some fluid in the near of the walls and the bubble cannot block the diameter.

[Taataa]

It would be buoyancy driven. There's just an air bubble inside the closed box.
I see. If by wetting you mean including contact angle, I have tried setting a constant alpha angle but didn't help.

[piu58]

Wetting means that there remains a fluid film at the wall.

[Taataa]

I appreciate it if you elaborate. What kind of boundary condition would you suggest?

[Taataa]

I just set the bc of alpha at the sides to a fixedValue of 1, and it's working, thank. Is that what do you mean? if so, is it scientifically acceptable?

[piu58]

Sounds reasonable.