Donut Sectioned Pipe Flow
 

Hello,

I am trying to reproduce an example of a laminar flow through a pipe. Like this:
https://s13.postimg.org/rkm44wmnb/Untitled.png

So I am trying to make a 2D analysis by drawing a rectangle and then use axial symmetry. The problem is that if I select the axis of the pipe as the axial symmetry axis, the Jacobian of the Navier-Stokes equation is gonna tend to infinite and I'm going to have bad results around this area. So the suggestion is that I take a small region around the axis out of the problem, by imagining the section of the pipe is a donut. Like this:
https://s13.postimg.org/r94ns567b/Untitled2.jpg

My problem is that I don't know how to make this geometry with axial symmetry.
When I select the axial symmetry axis, it can't be a line am I right? There has to be some kind of of body, and I only have one body which is a surface, and the axis is out of it. This axis is represented in blue here:
https://s13.postimg.org/3w6m9mq3r/Untitled3.jpg

Also, what kind of boundary should I select for the "wall" with the green question marks over it? It can't be a wall, because I want a velocity profile like this:
https://s13.postimg.org/hei3znrmv/Untitled4.jpg

Thank you all in advance,
Luís