Bubble detachement
 

Hi,
I'm new using Star, I use it only from 2015.
I would simulate a bubble detachement after the development of it, with gravity, from a velocity inlet. I'm using Eulerian multiphase-VOF interation with turbolence.
I have a problem. The bubble grows up but it doesn't detache and I don't know why!
Any help/information are very appreciated.
Thank you