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-   -   Overset mesh post-processing (https://www.cfd-online.com/Forums/ensight/187989-overset-mesh-post-processing.html)

HHOS May 19, 2017 12:03

Overset mesh post-processing
 
Hello everybody!

I just want to ask if there is any way to do the postprocessing of fluent cases where the overset function is used. Until now, the little postprocessing I managed to do was inside Fluent. In Ensight, the full meshes are displayed, not just the used part, so to speak.

Do you know if they are developing something related to the topic?

Regards.

kevincolburn May 20, 2017 00:13

Most overset mesh methods utilize/store/maintain the complete mesh domain, but also generate a "BLANKING" flag or variable to denote elements which are completely or partially removed from the computational domain. So, typically, most overset solvers will export the complete domain to the mesh/grid file, but then create a blanking variable (commonly referred to iblanking) which allows post processing programs to turn off/hide/blank elements appropriately.

So, have a look at the variables from the solver, and there should typically be some type of blanking variable. Make sure that you export/read that variable into the post processing software, and utilize it to blank out the elements appropriately.

-kevin

HHOS May 23, 2017 10:28

Thank you very much for the tip. It actually worked very well.

In case it is useful for somebody:

Working with Fluent, I had to export the "Overset_cell_type" variable. With that variable I do a isovolume for values [1,2]; that way I get the domain cells that are identified as "Donor" and "Solve".

That isovolume part(s) are my usual domain parts to work with.

ashishgehu November 17, 2017 03:29

can u please elaborate the procedure for ansys fluent . i want to export the data of fluent overset mesh solver to cfd post . please help me

Lenny December 8, 2017 02:15

Overset postprocessing
 
Hi, HHOS

Can you tell me what is your meaning of "isovolume value"? And I export the "overset_cell_type" values and I found that those value are not consistent with what they should be in the tutorial like 0,1,2,-1,-2. My value is always above zero and some of them are not even integer,something like 0.33,0.25,1.53,2.53. Did you meet this kind of problems? By the way, the FLUENT version I use is 18.1.

HHOS December 8, 2017 08:03

Well, first, I have no clue about CFD-Post, but I guess the procedure must be similar to that used in CEI Ensight (or maybe ANSYS Ensight now?).

Lenny, the isovolume part is something to be done in Ensight. I find weird that the "overset cell type" has those values you are saying. Maybe you exported something else?

Regards

Lenny December 8, 2017 08:35

Quote:

Originally Posted by HHOS (Post 674493)
Well, first, I have no clue about CFD-Post, but I guess the procedure must be similar to that used in CEI Ensight (or maybe ANSYS Ensight now?).

Lenny, the isovolume part is something to be done in Ensight. I find weird that the "overset cell type" has those values you are saying. Maybe you exported something else?

Regards

Thank you for your reply.
I checked my case again and I found that a information always come out when FLUENT exports data files. The information is:
"Overset connectivity information is only written to case files in HDF format. It is recommended that you write overset cases in HDF format(parallel solver required)". I don't know if that is the reason why those overset_cell_type values are not consistent with toturial. I will try to write date files into HDF format to see if it will work. Thank you.

Lenny December 10, 2017 21:28

Overset postprocessing
 
Hi,all! I get one problem solved. I figure out why overset_cell_type variables are not integer. That is because when I export data files into ASCII format, there is a "location" option(Node or Cell center) to specify the data location. I should have chosen Cell center instead of Node.


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