[Artur.Ant]

Hello to everyone. I try to simulate a flow in a tunnel with fluent.
I created two cell zone: air and tunnel.
For the air I have a velocity inlet and a pressure outlet.
The solver is transient, viscous model K-W, I created a mesh interface between air and tunnel and simulated two cases.
The first case is: two meshes at rest and I imposed the velocity with a velocity inlet v=40 (absolute frame of reference)
The second case is: the mesh air is at rest while the mesh tunnel slides on it with the velocity v=20 (absolute frame of reference).
I created some planes and integrated the pressure on it but the results in the two cases are the same.
My question is why the results are the same? is there a way to impose the roughness on the faces of tunnel mesh?
You can see in the picture the geometry after the simulation (the tunnel is slided on the air).