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-   -   No Report Files when changing to Transient (https://www.cfd-online.com/Forums/fluent/232447-no-report-files-when-changing-transient.html)

dakotav14 December 14, 2020 11:12

No Report Files when changing to Transient
 
Hi,

I'm trying to run a transient solution using a previously converged steady-state solution with report files for things like CD, CL, CS, etc. I changed my model, solver settings, and then edited my report-files to set frequency-of to time-step and the itr-index to 626 as my converged solution is set to 625 steps. However, Fluent is not writing anything to these files. I've double checked all of the reports are active and even tried adding completely new report-files and definitions but nothing is being written. I'm not sure if this is an error due to a mismatch between the previous iterations and then switching to a time-step? I don't have it set to flow-time so I would've thought it would carried onto the next iteration as is.

Thank you in advance!

AlexanderZ December 14, 2020 23:07

number 626 means fluent will write to file once each 626 time steps

change 626 to 1, so you will get data on each timestep

dakotav14 December 15, 2020 08:51

Quote:

Originally Posted by AlexanderZ (Post 790667)
number 626 means fluent will write to file once each 626 time steps

change 626 to 1, so you will get data on each timestep

I believe what you're talking about is controlled by the frequency option.

MKuhn December 16, 2020 01:54

You have to set it to 625 iterations. As you set the iterations per time step to 625, it will never reach 626 and therefore it will not write anything to your data files.

I would recommend to switch to flow-time or time step, in your way you have to ensure, that you have always 625 interations per time step to hit the converged solution, if not you will store the data of the first iteration, which will be nonsens.
Due to that fact, it could be possible that option "store every iteration" will not work in transient mode.

dakotav14 December 16, 2020 09:14

Quote:

Originally Posted by MKuhn (Post 790805)
You have to set it to 625 iterations. As you set the iterations per time step to 625, it will never reach 626 and therefore it will not write anything to your data files.

I would recommend to switch to flow-time or time step, in your way you have to ensure, that you have always 625 interations per time step to hit the converged solution, if not you will store the data of the first iteration, which will be nonsens.
Due to that fact, it could be possible that option "store every iteration" will not work in transient mode.

Oh I realize I may have worded my original post poorly. My converged steady-state solution ran to 625 steps, I am using that as my solution initialization. My iterations per time step is set to 5 not 625. I added an example line from my journal file below to possibly better describe what I have done.

/solve/report-files edit cl frequency-of time-step itr-index 626 quit

For what it's worth, my temporary work around is using the instantaneous values for the forces and making the frequency of my reports equivalent to the number of sub-iterations per time-step, ie if I have it set to sub-iterate 5 times, my report will report every 5th sub-iteration. It reports the data I want but my iterations count by 5. Not ideal but not exactly the end of the world.


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