This is a good question for, given your description of the geometry, the axis location is outside the computational domain.
Well, just select "2D axi-symetrical" in "Model", and make sure the cylinder direction is in X and its center (even if not part of the mesh) at the 0,0 location in Y,Z.
I (probably naively) believe that the solver should get it right. Check it carefully by reporting the "areas" of a couple of surfaces.
If it is not the case, maybe you should contact your user support, they should know better. Hopefully.
At the worse, you may simply have to mesh (coarsly) the smaller-radius cylinder, so as the axis is actually part of the mesh. If you solve for temperature and you do not want the inner cyclinder to play a role, just freeze the heat exchange at the separation-wall (heat flux 0 at the wall facing the cylinder, and whatever you want for its "shadow" facing the fluid). Does this make sense?
This is a good question for, given your description of the geometry, the axis location is outside the computational domain.
Well, just select "2D axi-symetrical" in "Model", and make sure the cylinder direction is in X and its center (even if not part of the mesh) at the 0,0 location in Y,Z.
I (probably naively) believe that the solver should get it right. Check it carefully by reporting the "areas" of a couple of surfaces.
If it is not the case, maybe you should contact your user support, they should know better. Hopefully.
At the worse, you may simply have to mesh (coarsly) the smaller-radius cylinder, so as the axis is actually part of the mesh. If you solve for temperature and you do not want the inner cyclinder to play a role, just freeze the heat exchange at the separation-wall (heat flux 0 at the wall facing the cylinder, and whatever you want for its "shadow" facing the fluid). Does this make sense?
Good luck...