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Static and time dependant application modes in same model

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Hi,

this might be a very stupid question...

In a model, where I have two different application modes:
- one application mode is purely stationary (e.g. the magnetic field produced by a permanent magnet; the field is not dependant on the other application mode nor on time)
- a second application mode, which is time dependant, and which requires a variable from the first one (e.g. the magnetic flux density) to compute a given value

How do I tell Comsol to compute only once the solution to the stationary application mode, and then make this solution available at any time t for which the second application modes computes a solution?

Thanks for any help.

Kind regards,

Alois Pfenniger

6 Replies Last Post 24 juin 2010, 11:08 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 24 juin 2010, 08:51 UTC−4
Hi

in 3.5 or 4 ?

in 3.5 read through the use of the solver manager tab settings, make a sequence first run, store the solution, execute it, and save the sequence in the sequenece tab, then run the second by using the restart from saved solition, save it too in the sequence tab. next time you hit run it will run both sequences as saved (if you enable the seuenced run tick in tha last tab of the solver manager).

In V4 you set it up in the solver sequence. But I had a surprise as COMSOl cannot always imagine which solver is attached to which physics in "automatic mode" therefore I have been explained that you can override the "automatic solver selections" in the/all main physics tabs, hit: Advanced + select solver + select other variables if applicable (user defined: frequency, sweep, time ..) do this for one or all of your physics, then generate a fresh study sequence, and check the appropriate restart intitial values conditions, do not forget that "variables not solved for" are those generally solved for" of the previous sequence a thing I always manage to mix up.

This worked for me, when I was coupling frequency induced Joule Eddy current heating from a coil into a conductive block, and running a transient analysis in the HT mode.

Hope this helps
Have fun Comsoling
Ivar
Hi in 3.5 or 4 ? in 3.5 read through the use of the solver manager tab settings, make a sequence first run, store the solution, execute it, and save the sequence in the sequenece tab, then run the second by using the restart from saved solition, save it too in the sequence tab. next time you hit run it will run both sequences as saved (if you enable the seuenced run tick in tha last tab of the solver manager). In V4 you set it up in the solver sequence. But I had a surprise as COMSOl cannot always imagine which solver is attached to which physics in "automatic mode" therefore I have been explained that you can override the "automatic solver selections" in the/all main physics tabs, hit: Advanced + select solver + select other variables if applicable (user defined: frequency, sweep, time ..) do this for one or all of your physics, then generate a fresh study sequence, and check the appropriate restart intitial values conditions, do not forget that "variables not solved for" are those generally solved for" of the previous sequence a thing I always manage to mix up. This worked for me, when I was coupling frequency induced Joule Eddy current heating from a coil into a conductive block, and running a transient analysis in the HT mode. Hope this helps Have fun Comsoling Ivar

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Posted: 1 decade ago 24 juin 2010, 09:16 UTC−4
Hi,

I am (still) using 3.5a.

Thanks very much for your advices .I exactly messed up the point with the "variables not solved for"... Now it works :-)

Alois
Hi, I am (still) using 3.5a. Thanks very much for your advices .I exactly messed up the point with the "variables not solved for"... Now it works :-) Alois

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 24 juin 2010, 09:44 UTC−4
Hi

good to hear, but do remember the issue in V4, currently it's not easy to identify, it took me several days and help from support, many things changes in V4, but basically it's cleaner, just tought to adapt in no time, as my boss is not paying me to learn, only to use ;)
Have fun Comsoling
ivar
Hi good to hear, but do remember the issue in V4, currently it's not easy to identify, it took me several days and help from support, many things changes in V4, but basically it's cleaner, just tought to adapt in no time, as my boss is not paying me to learn, only to use ;) Have fun Comsoling ivar

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Posted: 1 decade ago 24 juin 2010, 10:30 UTC−4
Hi,

I will remember the issue in V4. I just got used to 3.5a, and I will not change to V4 before my next simulation project. Is your boss paying you for kinkdly and quickly answering questions on this forum? ;-) If yes, tell him I really appreciate...

Alois
Hi, I will remember the issue in V4. I just got used to 3.5a, and I will not change to V4 before my next simulation project. Is your boss paying you for kinkdly and quickly answering questions on this forum? ;-) If yes, tell him I really appreciate... Alois

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 24 juin 2010, 10:34 UTC−4
Hi

PLS do not tell him I'm here :)

More serious, I have noticed that I learn quicker by answering some questions up here, because the problems I see are simpler, you concentrate only on the one issue, while when I come with my own models they are far more complex and I notice I get lost in this complexity specilly at the start with COMSOL. My learning curve of COMSOl has been boosted since the forum came on, and I could interact with others.

Ivar
Hi PLS do not tell him I'm here :) More serious, I have noticed that I learn quicker by answering some questions up here, because the problems I see are simpler, you concentrate only on the one issue, while when I come with my own models they are far more complex and I notice I get lost in this complexity specilly at the start with COMSOL. My learning curve of COMSOl has been boosted since the forum came on, and I could interact with others. Ivar

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Posted: 1 decade ago 24 juin 2010, 11:08 UTC−4
Hi,

I understand your point. Trying to identify and separate the different issues of a complex problem is indeed the key to success in comsol...

Alois
Hi, I understand your point. Trying to identify and separate the different issues of a complex problem is indeed the key to success in comsol... Alois

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