How to simulate a incomp fluid that falls due to gravity?
 

How to CFd an incomp fluid that falls off a certain height due to gravity using a staggered grid and finite volume method? ( there's no air, the fluid is in a vacuum chamber)
I know there are many algorithms, but in general, I guess I have to apply the gravity source term only where the fluid is (initial position) and then somehow move it forward, any suggestion? Problem is the cells where to apply the gravity source term are dynamic.
I'm actually using chorin projection method, SOR for solving pressure and the grid is a square grid with n^2 cells with ghost cells too.