RESULTS OF THE SIMULATIONS
We tried to simulate with a coarse mesh (only 10 cells in y direction)
and we have the following results on the velocity field.
U(inlet) = 1E-4 m/s
It seems that in the middle of the domain, the fluid moves as a block
but it is obvious that the mesh is not fine enough to precisely evaluate
the Bingham profile.
Simulation with refined mesh
In those simulations, we have used a mesh with 20 cells in y direction.
We can verify that the velocity field has the same appearance as before
and that on the velocity vectors view at x=7m, we clearly see that the
fluid moves as a block.