Actually in my simulation, I used water and carbon dioxide gas as a fluid and use Vof model, considering surface tension 0.072,boundaries conditions with inlet pressure from 2-10kpa and outlet pressure 0

Method is PISO time step size is 0.00001

Now in my simulation bubble size is small and no vortex is visible,

I don't know what is the problem of this error

How I get better results

I think my geometry mesh is not good enough which is suitable for my results.