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Creating pairs in model with moving mesh and magnetic field
Posted 9 juin 2010, 03:02 UTC−4 3 Replies
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Hi,
I am trying to simulate a model with three main domains, two of them being fixed, and the third one, in the middle, with a given vertical displacement as function of time. A magnet is placed in the domain on the left, and I want to observe the streamlines of the magnetic field throughout all domains.
I use so-called sliding meshes, and therefore set identity pairs between the three domains. Unfortunately, when I look at the results, it seems that the magnetic field is computed once at the beginning of the transient simulation, and that this same magnetic field does not change anymore in the domain which is moving, although it definitely should! The streamlines become discontinues, which should not happen.
Any idea what I set wrong in my model?
Thanks if you can help me.
Kind regards, Alois Pfenniger
I am trying to simulate a model with three main domains, two of them being fixed, and the third one, in the middle, with a given vertical displacement as function of time. A magnet is placed in the domain on the left, and I want to observe the streamlines of the magnetic field throughout all domains.
I use so-called sliding meshes, and therefore set identity pairs between the three domains. Unfortunately, when I look at the results, it seems that the magnetic field is computed once at the beginning of the transient simulation, and that this same magnetic field does not change anymore in the domain which is moving, although it definitely should! The streamlines become discontinues, which should not happen.
Any idea what I set wrong in my model?
Thanks if you can help me.
Kind regards, Alois Pfenniger
Attachments:
3 Replies Last Post 1 juil. 2010, 19:00 UTC−4
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Posted:
1 decade ago
Problem solved :-)
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Posted:
1 decade ago
Hi Alois,
where was the problem? How did you solve it?
cheers,
JM
where was the problem? How did you solve it?
cheers,
JM
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Posted:
1 decade ago
Hi,
I had to change many things, and I cannot tell you exactly what was responsible for my problem (probably there were several mistakes…).
You find below the exact instructions of what I changed in the first model for it to work. I also attached the working model to this post.
Multiphysics -> Application mode ALE :
Physics -> Properties :
- weak constraints : “off”
- analysis type : “static”
Draw -> Create composite object -> “R1+CO1”
Draw ->Create pairs -> “R2 C02” (without imprint)
Draw -> Create pairs -> “R2 R3” (without imprint)
Physics -> Subdomain settings:
3 -> Prescribed displacement -> “z1” in z direction
Multiphyics -> Application mode EMQA
Physics -> Boundary settings:
Everywhere, except for pairs and rotation axis and boundaries of magnet: “Magnetic insulation”
Both sides of both pairs: electric insulation
Rotation axis: axial symmetry
Boundaries of magnet: continuity
Deactivate “weak constraints” on all boundaries which are not moving
Physics -> Identity pairs -> Identity boundary pairs:
Make sure that for Pair 1, Source boundaries = 9 and destination boundaries = 8
Make sure that for Pair 2, Source boundaries = 12 and destination boundaries = 13
Under “Advanced”, make sure that for both pairs, all the frames are set to “Frame(ale)”
Add equation for displacement:
Physics –> Global equations
z1 z1-z2
Options -> Expressions -> Global Expressions
z2 0.09*t
(0.09 instead of 0.1 in the original model is just to avoid that at t=1s, the subdomain which is moving reaches the edges of the fixed subdomains, which gives an error in the solver).
Reset model to clear previous solutions (File -> Reset Model)
Initialize mesh and refine twice.
Solve :-)
Hope it helps. Regards,
Alois
I had to change many things, and I cannot tell you exactly what was responsible for my problem (probably there were several mistakes…).
You find below the exact instructions of what I changed in the first model for it to work. I also attached the working model to this post.
Multiphysics -> Application mode ALE :
Physics -> Properties :
- weak constraints : “off”
- analysis type : “static”
Draw -> Create composite object -> “R1+CO1”
Draw ->Create pairs -> “R2 C02” (without imprint)
Draw -> Create pairs -> “R2 R3” (without imprint)
Physics -> Subdomain settings:
3 -> Prescribed displacement -> “z1” in z direction
Multiphyics -> Application mode EMQA
Physics -> Boundary settings:
Everywhere, except for pairs and rotation axis and boundaries of magnet: “Magnetic insulation”
Both sides of both pairs: electric insulation
Rotation axis: axial symmetry
Boundaries of magnet: continuity
Deactivate “weak constraints” on all boundaries which are not moving
Physics -> Identity pairs -> Identity boundary pairs:
Make sure that for Pair 1, Source boundaries = 9 and destination boundaries = 8
Make sure that for Pair 2, Source boundaries = 12 and destination boundaries = 13
Under “Advanced”, make sure that for both pairs, all the frames are set to “Frame(ale)”
Add equation for displacement:
Physics –> Global equations
z1 z1-z2
Options -> Expressions -> Global Expressions
z2 0.09*t
(0.09 instead of 0.1 in the original model is just to avoid that at t=1s, the subdomain which is moving reaches the edges of the fixed subdomains, which gives an error in the solver).
Reset model to clear previous solutions (File -> Reset Model)
Initialize mesh and refine twice.
Solve :-)
Hope it helps. Regards,
Alois
Attachments: