asking for isolated fluid region
 

Hi:
I am doing a problem with free surface(3D).
I meet the no isolated fluid region.
I set up presurre level.But there is the same problem.
but , my model is in no free surface, there is no problem.
If I set the parameter of fress surface, it check no isolated fluid region.
At the same time,I have set the pressure level.
The reference pressure is relative air pressue? location(0,0,0).Right?
asking for help.