Indeed there is a problem with my mesh and with the piece of code I wrote to make it.
The z values of the inlet/outlet nodes don't correspond. I am trying to figure this out.
This bring a different question.
Since this is in cylindrical coordinates, is it better computationally to solve the whole thing in r, theta, z coord? Then it is a simpler translation between the inlet and outlet and my mesh will be simpler to build and be more accurate.
Thanks for your help.