Anybody has good idea of tracking multiple bubbles in VOF or level set method? It's easy to calculate the center of mass for one bubble. But for multipple bubbles, how to distinguish them? Any comments?

for this you need a region tracking algorithm,

an expensive way is to solve one poisson equation per region as disscused in this paper (like front tracking method): http://dx.doi.org/10.1016/j.jcp.2004.09.009

but a very cheap and rubost method (particularly suited for structured grid) is to use fast marching method disscused in appendix of this paper: http://dx.doi.org/10.1016/j.cma.2007.09.018

Dear Sir, I'm a graduate student and I'm also interessted to track more than one bubble using VOF method. I ask if you have make a progress in that field to help or to give me some references.

Many Thanks