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How to limit time step size, when time depend solver neglects Nyquist Theorem?

Posted 17 mars 2014, 15:30 UTC−4 Version 4.4 3 Replies

Hans Gennerich
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I have a boundary condition: Boundary Temperature varies as: 293.15[K] + sin(t/100[s]) * 1[K]

The Time Dependend Solver generates a time series beginning with
0,1,10,20,40,80,160,320,640,1280 ...
where the last time step obviously severely surpaces the Nyquist frequency limitation.
So it seems I have to set a limit for time steps manually.

How will I have to do that?

I attach a screen-shot of the problem

Attachments:

3 Replies Last Post 18 mars 2014, 11:53 UTC−4
Hans Gennerich
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Posted: 1 decade ago 18 mars 2014, 09:54 UTC−4
When I choose Study/Timed Dependent, there is no place to set a maximum time step size.
It needs one run, to let COMSOL generate a node "Solver Configuration". Opening this one I can dig deeper at: Study 1/Solver Configuration/Time Dependent Solver1/Maximum Step

But this option is only available after an initial faulty run, not during setting up the model for the first run. Correct?
When I choose Study/Timed Dependent, there is no place to set a maximum time step size. It needs one run, to let COMSOL generate a node "Solver Configuration". Opening this one I can dig deeper at: Study 1/Solver Configuration/Time Dependent Solver1/Maximum Step But this option is only available after an initial faulty run, not during setting up the model for the first run. Correct?
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago 18 mars 2014, 11:29 UTC−4

You can always show the default solver by right clicking the study node and choose from the context menu.

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You can always show the default solver by right clicking the study node and choose from the context menu. -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com
Hans Gennerich
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Posted: 1 decade ago 18 mars 2014, 11:53 UTC−4
Thank You, Yes I found it now.
Thank You, Yes I found it now.

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