Stokes flow 3D with mesh in GMSH

Hi everyone,
I appreciate any help about the following issue:
I’ve built my own geometry in FreeCAD then meshed in GMSH and finally converted in .xml format with succes.
When i run my code which is correct and works good also in 2D framework, I got the following output for the velocity which leads me to think about an error maybe in the mesh, but I’ve run the code on a pretty fine mesh.
I do not understand why the flow arrives so weakly towards the obstacle, regardless of the initial conditions that I set. The code and the geometry files are available in this folder:
The boundary conditions for the simulation are: inlet velocity = outlet velocity and on the upper and lower rectangle the no slip condition is setted.

I think this is a duplicate of 3D Stokes flow, meshed in gmsh

If you have any strong arguments as to why it is not a duplication please let me know.
Otherwise I will delete this post tomorrow.

In the previous answer I ask clarification about how my flow does not appear inside volume. Here I solved this issue, then I’m able to show the inner flow profile, but i don’t understand why it is so weak, for each initial condition I set.

See my reply in the other post. The is that you are not applying any boundary conditions on the side walls of your domain