In my simulation system there are two immisible liquid phases, one of them is in the right side of the simulation box and the other is in the left side in Z direction. In X and Y direction center of mass velocity is 10^-5 in read units and in Z direction the velocity is about 10^-4. Visually I see displacement of phase 1 by phase 2 periodically. I used periodic boundary conditions but I think after equilibration I should not see the displacement. Would you please help me about this?
Thanks alot for your time an d attention.