the hybrid initialization gives me a recirculation at the inlet leading to a non uniformity of the pressure field as seen above.

Aitor, Rob thank you because thanks to you I'm learning a lot about CFD and it's getting more and more interesting!

So I patched the input zone to pressure (170b) and the rest of the zones to 0B. I only saw your answer later about the velocity patch, I had already patched the velocity on the output zones v=0.

So I ran the calculation and I can start to appreciate the convergence of some residuals :
I stopped at 500iteration.

The velocity field is uniform and so is the pressure field:

can I appreciate some level of convergence with these elements?

The question I have now is about the y+. I should have a y+ =1 (roughly) but I have the max of y+ = 40 . I plotted the y+ and I noticed that the maximum value 40 is at the ball where there is the restriction of the passage (See image below). Should I reduce the height of the boundary layer in this area? Knowing that my orthogonal quality may decrease (here it is 0.09)?