appropriate boundary layer properties, k-e turbulence model

Hello,

I have been trying to simulate fluid flow thorugh a certain design, and I'm starting with half a cylinder to which I'll add geometric complexity.

The model does solve. However, the walls don't show velocity zero.

Is this due to the boundary layer properties? the mesh? I don't know where to start. I have tried a few variations on the mesh and boundary layer sizes, but I still have the same result. What are the optimal boundary layer properties for a fluid flow problem?

Thank you,
Sylvana