open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear all,
I am currently trying to simulate the flow behind a porous disk with Telemac3d. I am using a k-epsilon model.
My first question concerns the boundary condition for k and epsilon at the bottom. In the routine cstkepf, I understand that I can impose either Neumann or Dirichlet condition at the bottom. I have tried both types of conditions (LIMKF = 1 and LIMEF = 1 or LIMKF = 2 and LIMEF = 2) but, unless I am wrong, it gives exactly the same results. As the program always goes in kepcl3.f, I foresse that Dirichlet conditions are always used. Can someone confirm?
My second question concerns the boundary conditions for the velocity at the bottom. I am using a refined mesh near the bottom (first plane at z = 0.004m which is equivalent to y+ = 30). I have tried both conditions for the velocities (impermeable slip boundary condition or no-slip condition). The results significantly differ but they are both in fairly good agreement with measurements. Can someone tell me if one condition is more suitable than the other (as regards my vertcial discretization and my formulation for k and epsilon)?
Thank you.
All the best,
Jérôme