[MEDI]

Hi everyone
I want to model a flow around solids, but I do not want the solid in the calculation, I just want it to appear in the post treatment as presented in picture.
should I do something for solids during the definition of the geometry in workbench?
How should I mesh my model?
Should I mesh the solids?
what kind of mesh I should use?
what boundary conditions should I put on the walls of solid?
Help me please

[ghorrocks]

If you don't want the solids in the simulation then don't mesh them.

This is a REALLY basic level question - you really need to do some tutorials and examples as you clearly don't understand the basics. Do the tutorials provided with CFX and the examples on the CFX Community page on the ANSYS web page.

[MEDI]

With all the respect I owe to you Glenn, but I feel that you have not understood my question and you answered me quickly.
Obviously if I don't want the solids in the simulation, just do not mesh them (Basic)
But the problem if I do not mesh them, they will not appear in the solution as shown in the pictures (we'll see that cavities).

that is why I ask if there is a mesh died, just for display, as in some softwares of EFM.
So now I hope you have an answer to my question?

[ghorrocks]

CFX does not support inactive meshes. But the image you show can be done with the buildings as cavities. If you define the buildings as one wall and the streets as another then in CFD-Post you can assign them different colours and textures so they look better in the visualisations.

But the problem if I do not mesh them, they will not appear in the solution as shown in the pictures (we'll see that cavities).

I have no idea what you are talking about. The image you show had the buildings as cavities and the post processor was displaying the walls of the buildings. You don't mesh the buildings to do this.