Flux through Zone
 

Hi everyone

I would like to calculate the flux through a zone that I defined before.
My problem is that I do not know if I can use phi and if so, how I can use it.

But I think the easiest would be to get the surface areas of every face of the zone and compute the flux with the velocity. My problem is, how do I get the surface areas?
Especially if I use sample for a zone, the faces are triangulated...

My case is a building with streets around it and a courtyard in the middle and essentially I would like to compute the flux through this courtyard.

Any input is appreciated.

Cheers Adrian