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How to make two different time ranges periodic in time dependent study

Posted Mar 5, 2013, 2:07 p.m. EST Heat Transfer & Phase Change, Studies & Solvers Version 4.2 2 Replies

Chenxi Zhang
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Dear all,

I'm trying to simulate a multi-physics model and one of them is heat transfer. I'm giving a pulse heat source where I use periodic rectangle function. I define the pulse duration as "tt" and the period as "TT". TT is much larger than tt.
Then I use time dependent study and I would like to take 5 values of time in pulse duration and 5 more after that in ONE PERIOD to save computing time. In other words, I'd like to take different densities of values of time in different ranges in one period. And I can make it in only one period like "range(0, tt/4, tt)" and "range(1.01*tt, (TT-1.01*tt)/4, TT)".

My question is how to make this difference repeating in MANY periods.

Is there any expression using mod() to do this or another way?

Thanks in advance.

Best regards,

Chenxi
2 Replies Last Post Mar 6, 2013, 11:35 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 6, 2013, 1:25 a.m. EST
Hi

I believe there is only the "hard way" type it out, I have already suggested to COMSOL once, that they provide us with more "advanced" functions to generate time steps from a periodic signal (periods of periods ...) that must still be on their list somewhere, but they get so many suggestions ;)

Once you define periodic functions, do not forget to set the time stepping variable to "intermediate" or "strict" and do not leave the default "automatic" else COMSOL will skip over your periodic stepping

--
Good luck
Ivar
Hi I believe there is only the "hard way" type it out, I have already suggested to COMSOL once, that they provide us with more "advanced" functions to generate time steps from a periodic signal (periods of periods ...) that must still be on their list somewhere, but they get so many suggestions ;) Once you define periodic functions, do not forget to set the time stepping variable to "intermediate" or "strict" and do not leave the default "automatic" else COMSOL will skip over your periodic stepping -- Good luck Ivar
Chenxi Zhang
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Posted: 1 decade ago Mar 6, 2013, 11:35 a.m. EST
Hi Ivar,

Thank you for your reply. I really appreciate your suggestion.
Typing out all the ranges is the last choice but it works at least.
Look forward to hearing good news from COMSOL in some updates.
I have learned so much from your replies in other discussions.
Thank you again and have a good day.

Chenxi
Hi Ivar, Thank you for your reply. I really appreciate your suggestion. Typing out all the ranges is the last choice but it works at least. Look forward to hearing good news from COMSOL in some updates. I have learned so much from your replies in other discussions. Thank you again and have a good day. Chenxi

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