Boundary conditions partition

Questions and remarks about code_saturne usage
Forum rules
Please read the forum usage recommendations before posting.
Post Reply
quarian_engineer
Posts: 24
Joined: Wed Jul 01, 2015 8:35 am

Boundary conditions partition

Post by quarian_engineer »

Hello again,

I have some problems with the definition of boundary conditions in code_saturne. To create the mesh (with Salome 7.6.0) I did some partitions of the flow domain (partition faces are the red lines in the attached screenshot).

How can I define the BC's on these faces? If I define them as "free inlet/outlet" the simulation doesn't work. And there are not really that much choices =/

Thanks in advance,
S.
Attachments
Screenshot_2016-06-15_15-08-59.png
Yvan Fournier
Posts: 4070
Joined: Mon Feb 20, 2012 3:25 pm

Re: Boundary conditions partition

Post by Yvan Fournier »

Hello,

These faces should not be boundary faces, but internal faces (partitioning under SALOME is an intermediate step, to prescribe geometry constraints, but does not mean the final mesh should be split in disjoint parts). Under SALOME's SMESH, you can use "merge nodes" to merge the nodes from the partitions. Otherwise, under Code_Saturne, use mesh joining (selection criteria "all[]" if you can't do better) in the preprocessing stage.

Regards,

Yvan
quarian_engineer
Posts: 24
Joined: Wed Jul 01, 2015 8:35 am

Re: Boundary conditions partition

Post by quarian_engineer »

Hello Yvan and thanks again. I did merge nodes with Salome and it seemed to be ok; but there comes another problem: I defined the boundary groups with Salome as Inlet, Outlet, Airfoil and Farfield. After the export of mesh as a .CGNS file and after running the check mesh, I got the following info from the check mesh:

-----------------------------------------------
Groups:
"Group 24"
boundary faces: 60
"Group 25"
boundary faces: 200
"Group 26"
boundary faces: 540
"Group 27"
boundary faces: 80000
-------------------------------------------------


Obviously these groups are supposed to be Inlet, Outlet, Airfoil and Farfield. But if I name them so in the "definition of boundary regions", I get an error "Some boundary condition definitions are incomplete or incorrect."

If i name them "Group 24" and so on, I get an error
"Error parsing expression:
Group 24
^
Expected operator instead of operand.".

I think this could be some internal Salome error with export; but do I have some possibility to manage it with code_saturne and define the bc somehow?
Yvan Fournier
Posts: 4070
Joined: Mon Feb 20, 2012 3:25 pm

Re: Boundary conditions partition

Post by Yvan Fournier »

Hello,

Yes, this seems to be a bug/limitation of SALOME's CGNS export, but if you use the group names, you need to "escape" the blank spaces.

Possibly, some CGNS tools, like cgnsview (installed optionally with the CGNS installation) might allow you to "fix" the names (best solution).

Otherwise, with Code_Saturne, use "Group\ 24" instead of "Group 24" (if using the GUI; if using user subroutines in C, you need a "double" escape, so use "Group\\ 24"). For full details, check the user documentation (pdf).

Regards,

Yvan
Post Reply