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Saving transient Simulation after specified Real-Time

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Old   February 8, 2017, 07:43
Default Saving transient Simulation after specified Real-Time
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Hello,

I have a transient simulation with a real-time runtime of about 7 days. I want STAR-CCM+ to do an Auto-Save every 6 hours (real-time, not physical time).

I have set up the Total Solver Elapsed Time - Monitor and an Update Event Monitor Delta (with Delta 21600 s = 6 h). In the Auto-Save settigs, I set the Trigger to Update Event -> Monitor Delta.

But unfortunately, nothing happens. The Simulation is not saved after 6 hours.

Can anyone help me?

Best regards
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Old   February 8, 2017, 15:19
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Any time related triggers in STAR-CCM+ are related to the physical time in the simulation itself.
If you want to use the CPU time you can create a Solver elapsed Time report and use that value to create an update Event. But please consider the number of processors in your calculation.

Last edited by Schwob77; February 9, 2017 at 14:32.
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Old   February 10, 2017, 07:08
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Thank you for your answer.
As I mentioned in my first post, this is exactly what I did.

I created the Total Solver Elapsed Time Monitor. Then I created an Update Event (Monitor Delta) for the Elpased Time Monitor. In the Auto-Save settings, I set the trigger to Update Event -> Monitor Delta.

The simulation is not saved after my specified time.

Can anyone help me?

Thanks
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Old   February 10, 2017, 12:22
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Sorry, I have not read your initial post correctly. My fault.

I'm not totally sure, but I think a Delta Event means the difference between the criterion in the current time step or iterarion to the previous one. Not the one between the current one and the first one. Maybe you can double-check that in the manual.
I think in your case an asymptotic event fits better. Therefore you create an Expression Report with def. 21600-Total Solver Elapsed Time. If this goes assymptotically to zero it should be enabled.

For cyclic behavior you need to subtract TSET%21600 from 21600.

Last edited by Schwob77; February 12, 2017 at 14:14.
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Old   February 13, 2017, 04:11
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That's no problem.

I have checked the manual for the Monitor Delta again:
Difference Mode Non-Accumulated: The difference is calculated between the current monitor value and the value at the last satisfied iteration. This is an absolute difference, ignoring the intermediate values. When the delta is exceeded, the last satisfied value is updated, resulting in a new comparison point from which the next delta is evaluated.

Referrering to this explanation, I figured out the approach with the Total Solver Elapsed Time and the Monitor Delta Update Event.

I will try it with an Expression Report. Do I have to enable the Periodicity? Because I think, my case is periodic. I would set the periodic maxium to 21600 and the minimum to 0.

What do you mean with: "For cyclic behavior you need to subtract TSET%21600 from 21600".

Thank you again for your help!
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Old   February 13, 2017, 04:26
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I tried it with the expression report (with 30 seconds interval for testing).
The expression report does, what it should. I will add a picture of the plot.

But now the problem is the asymptotic Update Event. I think the settings for this update event can not be set in this way, that the event ist triggered at the 0 s point.
The settings are: Sample Count = 1, Delta Threshold = 0.0 s


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Old   February 14, 2017, 11:00
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i had a quicl try and cant get triggers to force a autosave
so another way to do it is to run the solve from within a java macro in a never ending do loop and every x number of iterations or timesteps do a check on the wall clock and if another 6 hours is up do a save
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Old   February 15, 2017, 03:39
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Thank you, I will give it a try!
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