Problem in flux calculation for unstructured mesh

User Support
1

I was trying to calculate flux for an unstructured mesh problem which is similar to the example example for Unstructured mesh given in the documentation. But in this case the output file of tallies calculation becomes empty. The code is given below. I have created the h5m file of the geometry using Coreform cubit with DAGMC plugin.
Untitled.ipynb (35.5 KB)

geometry.xml (337 Bytes)
materials.xml (451 Bytes)
tallies.xml (9.9 KB)
statepoint.100.h5 (1.7 MB)

Note: the example which is given in the documentation has run well

2

Hi @Sabyasachi! Thanks for inquiring about this. I’m a little confused because the tallies.xml file doesn’t contain a mesh filter with an unstructured mesh applied. Maybe it didn’t get added to the inputs?

-Patrick

3

Hi Patrick thank you for responding.

I have modified the code as per your suggestion, but it shows same result. The output file of tallies calculation is empty.
I am uploading the files related to the code,
model.xml (1.2 KB)

Untitled.ipynb (34.7 KB)

Screenshot from 2023-10-31 22-32-20
Screenshot from 2023-10-31 22-32-20738×188 2.24 KB

Please have a comment on it

4

Hi Patrick, If you get a time for this please do a comment on it… I think the problem is on the meshing of the unstructured mesh

5

Hi @Sabyasachi, thanks for the nudge! If it’s openly shareable (I’m assuming so as this is an exploration of the feature), can you send along the unstructured mesh file as well? If it’s too big for discourse you can drop it here: Box

6

Thank you for responding
I have submitted the file… please check and have a comment on it…

7

Hi Patrick,
I hope that you have received the documents which I have submitted in the given link. Do you get any solution of this problem? please give me some necessary information. This project is related to my undergrad project submission.
Thanks in advance

8

Hi @Sabyasachi,

I’ve taken a look at this. The unstructured mesh I found in that drop point, named dagmc.h5m I think, was a DAGMC model consisting of only triangles. When you run mbsize (a MOAB utility for providing element types and counts) what does the output show you?

$ mbsize dagmc.h5m

Let me know if I got that model name wrong, I’ve had a number of models dropped off this week so I may be getting them confused.

Thanks,

-Patrick

9

Thanks for your response. You have get the correct model name. As you have suggested, the output is given below,

Screenshot from 2023-11-16 10-09-04
Screenshot from 2023-11-16 10-09-04731×121 12.1 KB

yes you have got the right scenario that the DAGMC model is consisting of only triangles.
I have generated this dagmc model by applying the code export dagmc "dagmc.h5m" faceting_tolerance 1.0e-5 length_tolerance 5 using coreform cubit.
Please suggest me how do I solve this problem?

10

If the output above is from the mesh file you’re using as an UnstructureMeshFilter, the problem is that there are no volumetric elements in the file. You’ll want to create an appropriate tetrahedral mesh for the problem and apply that instead.

11

Hi Patrick. Would an appropriate unstructured mesh only contain tetrahedral elements? I have a mesh with triangles and tetrahedral elements that I am using for a flux calculation. However, I only get zeros for my flux values, so I was wondering if my mesh is good. Thanks.

`   type  count    total          minimum          average              rms          maximum         std.dev.
------- ------ -------- ---------------- ---------------- ---------------- ---------------- ----------------
    Tri  16734  5.6e+05           5.5747           33.693           34.612           72.169           7.9247
    Tet  24468  7.5e+05           3.2502           30.725           31.955           91.947           8.7807
1D Side 197010  1.6e+06                2           8.1149           8.3899           17.065           2.1303
 Vertex   8344`
12

Hrmmm that should work just fine… I’m not sure what’s going on in that case. Can you provide that UM file?