How to continute a CFX transient run without losing previous time steps result file?

Scar123111 · January 30, 2020, 17:32

When I run a transient project, I find it's not yet where I want it to be. So I decided to let it run a few more time steps. However, when it's finished, all the previous time steps disappeared, CFD-Post only shows time steps from the most recent run. How can I keep all the time steps in result even if I run it continuously multiple times?
For instance, I run 100 time steps then I decide to run 25 more, but after it's finished CFD-Post will only have time steps 100-125, time step 0-100 will be gone, even the result files are automatically deleted from the folder. It seems to be the case with all transient analysis, is there a way to keep all previous time steps and have all 0-125 time steps in CFD-post?
Thanks!

ghorrocks · January 30, 2020, 18:10

Yes, that is what CFX does when you continue a transient simulation.

Your post processing has to handle the transient data being spread across 2 or more results files. If you are generating an animation I recommend only saving the image frames (not the animation) so you can generate the image frames for each results file, combine them together and use an external package to generate the animation.

Scar123111 · January 30, 2020, 18:26

Quote:

Originally Posted by ghorrocks

Yes, that is what CFX does when you continue a transient simulation.

Your post processing has to handle the transient data being spread across 2 or more results files. If you are generating an animation I recommend only saving the image frames (not the animation) so you can generate the image frames for each results file, combine them together and use an external package to generate the animation.

I notice you can manually add time step in CFD-post, so if the software keeps the result files from previous time steps, it won't be a problem. But the problem is, it will delete the previou timesteps result files, is there a way to prevent the sofeware from deleting them?

Gert-Jan · January 31, 2020, 02:02

Do you perform your runs through Workbench? Or in CFX standalone, outside Workbench?

Scar123111 · January 31, 2020, 05:58

Quote:

Originally Posted by Gert-Jan

Do you perform your runs through Workbench? Or in CFX standalone, outside Workbench?

On workbench.

Gert-Jan · January 31, 2020, 06:14

Already thought so.

If you want to keep it, you need to duplicate your simulation set and continue from there. If you don't do that, Workbench will overwrite the old results. It assumes that you didn't like the old ones.

Alternatively, use CFX outside Workbench, using the CFX-launcher. Then your old results are kept (by Windows) when you continue from an old result. Experienced user do that all the time. I only use Workbench for the mesher. After that I quit asap. Brings me in full control over the files and what to keep or not.

Drawback can be that your computer fills up, if you don't clean up yourself. Or buy a larger HD.

January 30, 2020, 17:32	How to continute a CFX transient run without losing previous time steps result file?	#1
Scar123111 New Member Oscar Shen Join Date: Jan 2020 Posts: 4 Rep Power: 6	When I run a transient project, I find it's not yet where I want it to be. So I decided to let it run a few more time steps. However, when it's finished, all the previous time steps disappeared, CFD-Post only shows time steps from the most recent run. How can I keep all the time steps in result even if I run it continuously multiple times? For instance, I run 100 time steps then I decide to run 25 more, but after it's finished CFD-Post will only have time steps 100-125, time step 0-100 will be gone, even the result files are automatically deleted from the folder. It seems to be the case with all transient analysis, is there a way to keep all previous time steps and have all 0-125 time steps in CFD-post? Thanks!

January 30, 2020, 18:10		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,716 Rep Power: 143	Yes, that is what CFX does when you continue a transient simulation. Your post processing has to handle the transient data being spread across 2 or more results files. If you are generating an animation I recommend only saving the image frames (not the animation) so you can generate the image frames for each results file, combine them together and use an external package to generate the animation. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

January 31, 2020, 06:14		#6
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,835 Rep Power: 27	Already thought so. If you want to keep it, you need to duplicate your simulation set and continue from there. If you don't do that, Workbench will overwrite the old results. It assumes that you didn't like the old ones. Alternatively, use CFX outside Workbench, using the CFX-launcher. Then your old results are kept (by Windows) when you continue from an old result. Experienced user do that all the time. I only use Workbench for the mesher. After that I quit asap. Brings me in full control over the files and what to keep or not. Drawback can be that your computer fills up, if you don't clean up yourself. Or buy a larger HD. falsc233 likes this.

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