Bathtub vortex and realated gas entrainment simulation in Fluent
 

Hi guys,

my aim is to simulate a bathtub vortex and the related gas entrainment phenomenon in Fluent; I'm trying to use VOF (with the Geo-reconstruct algorithm) but it seems not able to reproduce well the air/water interface and neither the vortex itself.
(I am sure, from experimental observation, that with the given boundary conditions the vortex is present!)
Any tips are welcome!
Thank in advance,

Andrea