MESH of complex geometry

[sophie Lu]

Hello,

I want to process complex urban ground as a MESH simulation. Now I have generate MESH of buildings successfully from DSM file. In this case, how can I extract the air area above the city? I have tried to generated a box that can cover the buildings and do Boolean cut, but it always warning that "cut cannot produce".

Is there any reference example or suggestion?

Thanks for your help!

Sophie

[louis.simvia]

Hello,

What software are you using to generate the mesh ?
According to what I understood, if you are using Salome shaper module to make the geometry, here is a video of how to make the mesh of the fluid domain around a house. You may find some tips that are related to current issue.
Let me know if this helps.

[sophie Lu]

Hi Louis,

Thanks for your reply. I want to generate multiple buildings and do some simulation about air pollution. I am using geometry and my MESH can be generated by using NETGEN 1D-2D-3D, but the model always said mesh quality is not good. I know its better to generate the mesh as hexahedral, but since my geometry has multiple buildings which means has multiple shells, it can not process to be hexahedral. Do you have any advice for this shpe process?Thanks!

[Yvan Fournier]

Hello,

Which model are you referring to in

the model always said mesh quality is not good

? If you are using code_saturne's mesh quality check, keep in mind that the indications are not "absolute". Quality issues detected may make it harder to converge and lead to a less stable computation, but there is no fixed/known threshold where the computation can or cannot run. The main idea is to visualize the quality criteria to determine where you could improve the mesh.

When using a mesh with tetrahedra, adding a viscous/boundary prisms layer, and extruding the mesh a bit at outlets can definitely help make the computation more stable.

Best regards,

Yvan