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HELP PLEASE! How to plot Time-Averaged variables in CFX???

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Old   September 26, 2016, 22:56
Default HELP PLEASE! How to plot Time-Averaged variables in CFX???
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Roberto
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Having read the "Time average results in Transient CFX Simulation" thread aroused a simple matter, a doubt, which I don't know if I got it right or wrong...

I need to calculate and plot some time averaged variables in CFX but I didn't activate the "Transient Statistics" under the "output control->TrnStats" in CFX Pre, just because I did not know what was this setting for (as you might guess, I'm pretty new in the use of ANSYS CFX).

The simulations are in transient regime.

Is it still possible to get these calculations on the variables I need, along with their correspondent plots or have I gone all wrong on it and have to re-run the simulations?

The simulations are quite extense and I would want badly to avoid doing them again...

Thanks in advance to any of your helpful replies!!!!
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Old   September 27, 2016, 02:38
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If i understood your question well, you need plots of CFX variables with respect to your simulation time..?
You would not have to rerun the simulation and CFX-Post could do that for you.. just explore the 'plot' section of the module..
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Old   September 27, 2016, 02:53
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As far as I can see, there are 2 ways for time averaged results:
1) Create a Monitor point with time averaging (Max, Min, Avg, etc) - this will be saved to the *.res file for every time step and can be extracted via monitor in solver manager or cfx5mondata command.
2) Create a *.trn file every n iteration with the desired variables.

In case you have saved some *.trn files, you can loop through them with a script and extract the desired data. The averaging has to be done manually in Matlab for example. Or use "Velocity.TrnAvg" etc. variables.
Alternate way: create a plot in Post with the time on one axis. Caution: Hitting apply let's Post loop through all *.trn files, which might take long.

If you don't have any *.trn files and have no monitor points set up accordingly, you only have the results of the last time step in your *.res file.
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Old   September 27, 2016, 09:15
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Seems as if this thread
http://www.cfd-online.com/Forums/cfx...imulation.html
could contain all answers needed
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Old   September 27, 2016, 20:40
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@fresty, I explored the plot section, but I deleted some .trn files because of storage spacing issues, so I don't know if that is the reason why I cannot get the plot, cause it might be looking for the other .trn files but is only finding the latest one...

And, yes... I need the time average of temperature and pressure. I need those variables averaged through the simulation time, on some specific planes
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Old   September 28, 2016, 01:33
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As I said in my previous post...have a look at script files.
And for your storage space issues...you know that you can reduce the size of the trn files by writing out only "selected variables" instead of the "standard" setting?!?
And if you chosse a bigger, but still reasonable, time interval to write out the trn you will easily reach a reduction by a factor of 10 to 100 in storage space.
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Old   September 28, 2016, 12:09
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Quote:
Originally Posted by monkey1 View Post
As I said in my previous post...have a look at script files.
And for your storage space issues...you know that you can reduce the size of the trn files by writing out only "selected variables" instead of the "standard" setting?!?
And if you chosse a bigger, but still reasonable, time interval to write out the trn you will easily reach a reduction by a factor of 10 to 100 in storage space.
I suspected it but wasn't sure that would reduce the size and by some reason (I cannot remember it now ) I didn't do it nor did I research that topic, but now that you mention it, I realise it!!! That is quite helpful!!!!!!

The scripts method you say, sounds very good, the problem is that I don't know any programming languages like Perl. That is why I'm always asking for another way to do it.

I wouldn't know how to write down a script to loop through the very few .trn files I have, that's why I asked (don't remember if it was in this thread or another) if just running another simulation having previously set in Pre all the Monitorpoints and .TrnAvg files you and -Maxim- have been replying me about, would be easier for me...

Being that said, what do you think, monkey1? would there be a simpler way to do it or should I go through it with one more simulation?

Btw, thanks for your replies... they have given me many hints on all the topics on which I have doubts. I just have to organize all the hints, ideas and info together to figure out how to proceed.
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Old   September 29, 2016, 01:32
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The "easier way" is the one you're refraining from: using a perl script
Maybe you should have a look at it. t is already in a form, that you would only have to replace some variable names...but it is up to you.
If you don't want to do so, then your only practicable solution is to set up a new run where you activate all the outputs needed.

Quote:
Btw, thanks for your replies
You're welcome. That's what such a forum should be there for.
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