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eishinsnsayshin January 18, 2013 14:19

Split boundary zone in FLUENT for mass flow
Hey everyone,

I'm trying to track mass flow through the front of a box (basically) using FLUENT. Incompressible flow. Perfect box. Box has an inlet, outlet, and walls everywhere else. So this will sound strange but I really only want the mass flow through the "inlet" of the box. It sounds strange because you're probably thinking the mass flow through the front and back of the box should be the same. And they will be...

The problem is that the inlet and outlet of the box are actually set as the same name. Lets say they're both called "inlet" in FLUENT. So if I track the mass flow through the surface "inlet" I will get exactly twice what the answer should be. So it shouldn't be an issue... I'll just divide what fluent gives me by 2. Buuuut it turns out the normal directions on the front and back surfaces of the box are opposite each other, so when I look at mass flow through the surface "inlet", I actually just get zero.

So to solve this now, I actually want to be able and take part of my surface "inlet" (either the upstream or downstream face) and rename it, so that the front and back of the box are both called something different.

Is there a way to do this exclusively in FLUENT? Maybe by x location or something? The reason is that this is a converted OpenFOAM case whose mesh was created using snappyhexmesh. All I was given is the fluent case file and have access to nothing else.

The only other option I can think of is to somehow reverse the normal direction on either the front or back face of surface "inlet", so I can divide by 2.

Is this even possible?

Thanks for any ideas!!!

eishinsnsayshin January 18, 2013 14:43

Uhhhhhhhhhhhhhhhhhhhh so nevermind. Mesh>separate>faces. Specify by angle. I hate when I put a lot of work into describing my problem and run across the answer 20 minutes later

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