1- yes it doesn't changed with time.

2- Yes I activate the gravity in my -ve Y direction.

3- CSF model .

4- Explicit VOF, with 0.01 second time step and (0.25) Courant number.

5- For 300 time steps and Max. iteration/ time step=1.

6- B.C :
     a) zero velocity inlet air velocity i.e in water multi-phase I entered that the volume fraction with zero.

     b) the upper boundary is a wall.

     c) the lower boundary is a contact with  90 degree as in the attached .

     d) the rear boundary is a pressure outlet with zero back flow water volume fraction.