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Changing boundary faces to interior faces

Posted: Sun Apr 11, 2021 9:12 pm
by mattfalc1997
Hi,

I am using ICEM CFD for mesh generation exporting it to Code_Saturne 6.0.5 via CGNS. I have constructed a quarter model of the domain and used ICEM to mirror the mesh in two directions to create the full domain. Necessarily the surfaces on the interface between the mirrored components contained boundary faces prior to the mirroring however this should no longer be the case after mirroring. The listing file indicates that there are still some boundary faces which means that the simulations are crashing as there are undefined boundary faces.

I was wondering whether these faces can be forced to become interior faces, it would also be useful to understand how Code_Saturne determines something to be a boundary face and whether this error is indicative of a 'hole' in the mesh due to the mirroring process. I have attached some images and the listing file. The images show the geometry and the post-processed boundary faces with the additional boundary faces. I also added an initial user subroutine written to try and force the faces to interior faces, although it was speculative, and it hasn't worked (it compiled fine and crashed in the same way).

Thanks in advance,
Matthew Falcone

Re: Changing boundary faces to interior faces

Posted: Sun Apr 11, 2021 11:06 pm
by Yvan Fournier
Hello,

In code_saturne, faces belonging to a single cell are boundary faces, faces belonging to 2 cells are interior faces (if the 2 cells are on different sides), and faces belonging to no cell are isolated faces (and discarded). Meshes with faces with more than one cells on the same side are rejected.

You can visualize the postprocessing output using the "mesh quality" or "preprocessing only" modes.

Check the available operations for mesh preprocessing in the GUI. Face joining joins neighboring boundary faces (splitting them into conforming pieces if non-conforming) to transform them to interior faces. The theory documentation provides more details relative to mesh quality aspects for non-conforming cases.

Regards,

Yvan