CFD-post only shows one timestep and no variables

lconstantin · May 7, 2017, 13:13

I ran a transient simulation and I have selected all the relevant variables to be exported as results. When I look in CFX-post it only shows me the last timestep and I cannot see any variables (except for trivial ones - X, Y, Z). Do you have any idea why? It took 7 hours for the simulation to run, it would be a shame to have to take it from the beginning

.

Thank you!

ghorrocks · May 7, 2017, 18:42

For a transient simulation you need to use transient result files. If you used backup results files (which look similar) you might not get any results.

lconstantin · May 8, 2017, 14:07

Quote:

Originally Posted by ghorrocks

For a transient simulation you need to use transient result files. If you used backup results files (which look similar) you might not get any results.

Thank you for your reply! I don't understand though, how do I use the transient result file?

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ghorrocks · May 8, 2017, 19:12

Set them up in the output tab. You have backup files and transient results. Don't use backup files, just use transient results.

lconstantin · May 10, 2017, 05:12

Are you refering to this?

Using these settings, I obtain:

So basically no results and data for only one timestep (the last one). Am I doing something wrong?

ghorrocks · May 10, 2017, 08:29

No idea. Your images did not get on your post. Read this FAQ: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F

Another way how you can stuff up results files is by having a moving mesh simulation, but then not including the mesh in the transient results files. You will only get a single result at the end of the simulation if you do this.

lconstantin · May 10, 2017, 11:01

OK, sorry for that. I replaced the images.

Opaque · May 10, 2017, 11:51

Perhaps a more detailed description would have helped.

From your images, you are not running a "transient analysis", you are running a "transient blade row analysis", correct?

For transient blade row analysis, the data is compressed into Fourier coefficients. Those Fourier coefficients are accumulated along the run, and if you stop the run before they are completed nothing is available for post-processing. There should be several messages in the output file:

1 - details, when the Fourier accumulation starts and finish
2 - warning if the solution has been stopped and the accumulation has not been finished.

In addition, when you load the results file in CFD-Post, look for "Calculate Variables using Fourier Coefficients" in the dialog (bottom right), and unselect it. Then, you should be able to post-process the last timestep w/o Fourier compression.

Hope the above helps,

lconstantin · May 10, 2017, 13:05

Oh, my fault. Yes, it is a transient blade row analysis. I didn't run it until the end, and I thought that I misunderstood that the results shouldn't be available, but it makes sense now.

Thank you very much for your help, you two!

May 7, 2017, 13:13	CFD-post only shows one timestep and no variables	#1
lconstantin New Member Join Date: Sep 2016 Posts: 9 Rep Power: 9	I ran a transient simulation and I have selected all the relevant variables to be exported as results. When I look in CFX-post it only shows me the last timestep and I cannot see any variables (except for trivial ones - X, Y, Z). Do you have any idea why? It took 7 hours for the simulation to run, it would be a shame to have to take it from the beginning . Thank you!

May 10, 2017, 05:12		#5
lconstantin New Member Join Date: Sep 2016 Posts: 9 Rep Power: 9	Are you refering to this? Using these settings, I obtain: So basically no results and data for only one timestep (the last one). Am I doing something wrong? Last edited by lconstantin; May 10, 2017 at 11:00.

May 7, 2017, 18:42		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	For a transient simulation you need to use transient result files. If you used backup results files (which look similar) you might not get any results.

May 8, 2017, 19:12		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Set them up in the output tab. You have backup files and transient results. Don't use backup files, just use transient results.

May 10, 2017, 08:29		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	No idea. Your images did not get on your post. Read this FAQ: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F Another way how you can stuff up results files is by having a moving mesh simulation, but then not including the mesh in the transient results files. You will only get a single result at the end of the simulation if you do this.

May 10, 2017, 11:01		#7
lconstantin New Member Join Date: Sep 2016 Posts: 9 Rep Power: 9	OK, sorry for that. I replaced the images.

May 10, 2017, 11:51		#8
Opaque Senior Member Join Date: Jun 2009 Posts: 1,803 Rep Power: 32	Perhaps a more detailed description would have helped. From your images, you are not running a "transient analysis", you are running a "transient blade row analysis", correct? For transient blade row analysis, the data is compressed into Fourier coefficients. Those Fourier coefficients are accumulated along the run, and if you stop the run before they are completed nothing is available for post-processing. There should be several messages in the output file: 1 - details, when the Fourier accumulation starts and finish 2 - warning if the solution has been stopped and the accumulation has not been finished. In addition, when you load the results file in CFD-Post, look for "Calculate Variables using Fourier Coefficients" in the dialog (bottom right), and unselect it. Then, you should be able to post-process the last timestep w/o Fourier compression. Hope the above helps,

May 10, 2017, 13:05		#9
lconstantin New Member Join Date: Sep 2016 Posts: 9 Rep Power: 9	Oh, my fault. Yes, it is a transient blade row analysis. I didn't run it until the end, and I thought that I misunderstood that the results shouldn't be available, but it makes sense now. Thank you very much for your help, you two!