Holed surface in a channel

[chrivero]

Dear all

I'm trying to analyze the flow of air due to a divergent and i want to see how the fluid behaves when hits an holed surface (as in the figure). I'm not really interested in the surface itself but of course i have to build a very small size mesh in the near fluid. When i try to start the mesh i have some problems. Is there any way to consider only the mesh in the fluid without generating it also in the surface body? Is there any trick to reduce the size only in that close zone?

Thank you

[Rob]

You may want to look at Porous Media in Fluent - knowing what the solver does is an important part of building the geometry. 

[chrivero]

Thank you for your answer. I tried to do this approach because if I enable porous media the velocity inside the packed bed is all constant and I can't see any difference in radial direction as I expect 

[Rob]

Then you need the holes, or Fluent's perforated wall model. For the former that means geometry and mesh is required.