Liquid height incrases in steady-state multiphase VOF
 

Hi,

The goal is simulation of water-air multiphase flow with Fluent in a steady-state mode and mrf (multiple reference frame). Height of the patch region for air (phase-2) is 17 mm inside a 57 mm height mixing vessel; 40 mm is water [figures are attached]. After about 1500-2000 iterations amount of liquid (water) starts to rise up until the tip of the tank, and amount of air decreases!! Contours and report of volume integral also shows the same trend. amount of water increases, while there is no sourse of any form...

* Tank top section is set to pressure outlet with backflow volume fraction for air 1.
* VOF model and also Eulerian-Multi-fluid VOF model were tested.

I do appreaciate any help and comments.