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AC field boundary condition
Posted 6 mag 2010, 10:59 GMT-4 2 Replies
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Hi all,
I want to study the magnetic field of a certain metal part in 3D inside a homogenuous external low frequency (150 kHz) AC field. I want a time-harmonic analysis.
I thought the best way to generate the external field (say it is homogenuous in z-direction) is to define the field at the outer boundary. This means the boundary would oscillate at 150 kHz.
In the AC model it doesn't work. Am I missing something here? I did a similar magnetostatic study this way and it worked, the boundary generated a homogenuous field.
Thanks and best regards
Edgar
I want to study the magnetic field of a certain metal part in 3D inside a homogenuous external low frequency (150 kHz) AC field. I want a time-harmonic analysis.
I thought the best way to generate the external field (say it is homogenuous in z-direction) is to define the field at the outer boundary. This means the boundary would oscillate at 150 kHz.
In the AC model it doesn't work. Am I missing something here? I did a similar magnetostatic study this way and it worked, the boundary generated a homogenuous field.
Thanks and best regards
Edgar
2 Replies Last Post 7 mag 2010, 04:41 GMT-4
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Posted:
1 decade ago
Hi
first of all COMSOL web site seems not to scale down images (again), yours is getting huge, this has happened before, send a mail to "support "and refer to the thread, they will fix it, they have probably forgotten to update their new site, following bug updates and testing new versions is tedious !
So back to your issue, are you sure it's not OK ? in harmonic the field is always maximum at a phase of "0", no ?
So by default you see a static case, you need to sweep the phase results to see the variations, this depdens on how you set up your model so I might be wrong here, I'm working from "memory" on a case I had some months ago
Hope this helps on the way
Have fun Comsoling
Ivar
first of all COMSOL web site seems not to scale down images (again), yours is getting huge, this has happened before, send a mail to "support "and refer to the thread, they will fix it, they have probably forgotten to update their new site, following bug updates and testing new versions is tedious !
So back to your issue, are you sure it's not OK ? in harmonic the field is always maximum at a phase of "0", no ?
So by default you see a static case, you need to sweep the phase results to see the variations, this depdens on how you set up your model so I might be wrong here, I'm working from "memory" on a case I had some months ago
Hope this helps on the way
Have fun Comsoling
Ivar
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Posted:
1 decade ago
Hi Ivar,
I uploaded a 50x50 pixel picture.
Now for the issue: You are right, it works as expected. I tried it again with a very simple model, it worked. I tried it with my more realistic model, it failed.
Finally I had to build up the geometry again from scratch and now it works. I don't know what went wrong before.
Actually at 0 degree phase I see the maximum field interaction because the temporal field derivative is maximum at 0. The field gets stationary at 90 degrees. COMSOL is probably using a sine and not a cosine to implement the time harmonic property.
Thanks for encourageing me to try it again.
Best regards, and yes, I am having fun comsoling,
Edgar
I uploaded a 50x50 pixel picture.
Now for the issue: You are right, it works as expected. I tried it again with a very simple model, it worked. I tried it with my more realistic model, it failed.
Finally I had to build up the geometry again from scratch and now it works. I don't know what went wrong before.
Actually at 0 degree phase I see the maximum field interaction because the temporal field derivative is maximum at 0. The field gets stationary at 90 degrees. COMSOL is probably using a sine and not a cosine to implement the time harmonic property.
Thanks for encourageing me to try it again.
Best regards, and yes, I am having fun comsoling,
Edgar