Hi all, I am new to fluent. Just runned a cavity driven flow, it worked, so I want to give multiphase flow a shot, but stucked at vof bc setup.

Here's my testing case, similar as cavity driven, now I have two fluids, one on top of another one, both surrounded by walls. The top wall will move at v1 when starts.

I read the manual, so I know how to setup two phases. What I did is to set "WALL" bc to all walls except the top one which I set it have moving velocity v1.

Ok, now is confusing part. Where shall I specify which mesh belongs to phase 1 and which mesh belongs to phase 2. I read tutorial example of fluent and couple of threads here, figured out "Inlet pressure" will let you setup vof value of one fluid and from what I read, it looks like the bc can be specified for both phases.

So here's my question. In general, how do I specify bc for each phase and how to assign phase to mesh? and maybe how to setup mesh for phase(ex. Gambit)? technically in fluent.

Thanks.

Best Regards

I figured out I should use "patch", but before I iterate, I plot the phase1 or phase2 vof number, it's 0 for phase1 and 1 for phase 2 everywhere. This is not what I want.

First I don't understand why both phase have vof number, I thought it supposed to be a single value which indicate the ratio between them. What I expected is that the vof num is 0 at phase1 and 1 at phase2 initially and they'll change afterwards.

Second I don't understand why only vof number of phase2 can be set initially.

Third fluent doesn't let me define where is phase1 and phase2, the only place I can think of is through "patch", but patch only let me do phase2.

I am using vof model. Really confused. Hope someone help.

Best Regards Fang