what does phi>=0 or phi<=0 mean?
 

1)I have a doubt about which direction phi indicates.if we have boundary patch at left the domain does phi<0 mean flow inlet and phi>0 indicate outflow?and viceversa for the patch in right of the solution domain(phi>0:outflow and phi<0:inflow)?
2)is normal() to patch always outside of the problem domain?

am i right?yes or no?

Hi, in boundary faces the only solution is to have the owner cell within the domain, so that, since the normal is ever pointing from the owner to the neighbor, the face area vector is ever pointing outside the domain.

Regards.