Residence time in VoF-model

Andreas

Hello everybody,

I've got a vof-model of a zylinder filled with water and air. There is a velocity inlet at the bottom (water), a pressure inlet at the top(air) and a pressure outlet.

I want to study the displacement of "old" water by "new" water.

Species dosen't work with VoF and defining two water-phases (old and new) is no option as well, because VoF-phases may not be interpenetrating.

One workaround I thought of, was to create a new one-phase model with the previously optained water-air-interface-contour as a frictionless wall.

If anybody has some solution to my problem or could advice some link/literature/...

Thanks, Andreas