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-   -   Post processing shortcut? (http://www.cfd-online.com/Forums/fluent/49022-post-processing-shortcut.html)

Ianto August 15, 2008 19:21

Post processing shortcut?
 
Dear All,

When postprocessing multiple simulations of the same geometry, instead of setting up custom field functions, chart axes etc for the required properties in each separate case file, I hoped to set them up in one master postprocessing case file, read each set of solution data into it and save out the required graphs etc, thus removing the need to define these each time.

However, when I do this and check contours etc, I find the solution is not the same as when the original case file is used - my inlet profile goes from having fully developed boundary layer to zero velocity. I've included the inlet boundary layer profile files from the original solution, and tried one iteration- it starts to adopt the required profile but basically needs to be solved for the new case.

Can anyone sugest why it doesn't work as I expected, and if there is any way of copying custom field functions into each case file without having to write them out each time?

Thanks,

Ianto

CDE August 17, 2008 19:10

Re: Post processing shortcut?
 
you can save the custom field functions to a file and read that into each case file.

you might be able to use a journal file to do your post processing

Ravi Shankar August 20, 2008 08:21

Re: Post processing shortcut?
 
Hello Ianto,

xxx.CAS, Case files are those consists of all Inputs to the problem setup with a model. For multiple simulations of multiple inputs, you may have to save these case files, to retrieve for Post processing.

xxx.DAT, Data files are those consists of all simulation results. Alter you may Start Multi simulation and save only Data files. And this is MUST for Post processing and to generate plots. These data files also helps you for Animations.

Best Regards.

Ianto August 20, 2008 09:25

Re: Post processing shortcut?
 
Thanks very much for both your suggestions.

I understand the relevance of .dat and .case (I think!), but expected I could postprocess with the .dat file only, using a case file with the same mesh but not, for example the exact turbulence model and other parameters.

I hoped, for expediency, to create a "baseline" case file with appropriate mesh and all required custom field functions, planes etc, then read each .dat file and extract the required data. I'm still not clear as to why this fails - when I read a .dat file without the original .case I get an incorrect inlet velocity profile (the original inlet profile file IS included in the new case)

CDEs solution is better (thanks!) - to create a journal and run that in each original case and data file. I've also realised the custom field functions can be saved out and read back in to the next case file so no need for laborious redefining in each new case.

So, in short, a procedure for quick postprocessing of multiple simulations of the same geometry will be -

(Assuming each case & data is in a separate directory)

Read in one case & data file

Create all required custom field functions and save them out

Start a journal

Read back in the custom field function file

Create all required planes/lines/rakes etc

Output all required contour/XY/vector plots etc

Stop the journal

Copy the custom field functions and journal file to all directories containing a case & data to be processed

Change to next directory for processing

Load case & data

Run journal

I think this should work, I'm about to try - I'll post back if there is any problem with this method!

Thanks again!



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