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mesh error
Posted Jan 31, 2013, 11:25 a.m. EST Low-Frequency Electromagnetics Version 4.3a 8 Replies
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I was trying to follow the PDF on comsol website ( Model ID 15) to build a model for Helmholtz coil. I followed almost all the steps except for the dimensions, so the geometry should have no problem. But when I was trying to compute the results, it gives me error saying that "not all domains are meshed, no mesh on domains 1,2", which are the domain for air. I have already set default domains to air and I did not see anything mentioned in the PDF about creating a mesh for air domains as well. Can you help me solve this problem so it won't give me a error? Thanks.
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be sure you have a last meshing sub-node stating "remaining" i.e. thets, that should ensure all domains are meshed
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Good luck
Ivar
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Thank you for your reply. When you said the last mesh sub-node, do you mean in Free Tetrahedral, set the geometric entity level to remaining? I thought i have to choose the coil for the domain.
Thanks!
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You might have several nodes, or other mesh command nodes, but it's always best to finish with one generic, stating "remaining" to ensure you have meshed all domains.
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Good luck
Ivar
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it actually worked after i changed the setting to remaining. Thank you!
and also, i have one more question. on the case example pdf from comsol website, it created the air box by revolving around the axis, so there is only one domain for air, and each coil only count for one domain as well. But it keeping giving me an error when I was trying to revolve around the existing 3D model i have. So instead i did extrusion based on xy plane, so it is gonna to have two domains for air, and also cut each coil into two different parts. So now, I will have 4 domains for 2 coils. but when I created mesh for the left/right coil, I did select both 2 domain. and I put the number of turns and current just as how it is. So is it gonna to give me a wrong answer when i compute the model Since the air cut each coil in half? Thank you.
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more questions.......
in 3D Plot Group 1, arrow volume 1, when i set everything the same as it is in the example for Helmholtz coil example, it plotted really big arrows, i assume choose proportional is proportional to the magnitude of magnetic field? Why mine is so big..... and also, mine streamline won't even plot, but it doesn't give me an error either...... So what might be the cause of that? How can i get everything to work?...... Thanks!
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for domains, I often split mine into several to be able to better mesh them, So long you select all related domains, and you use COMSOL Geometry "Union" mode with default continuity on domain boundaries you should be on the safe side and get correct results
If you have a complex geometry, adding a box or a cylinder "of air" around mostly works, but sometimes, the geometry imported is so complex that the domain splitting is not done 100%, then its worth to try the operation in the CAD tool
Arrows scale at best, depending on your object and the values you have you might need to change the scaling or the proportionality, the tabs are there for you ;)
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Good luck
Ivar
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thank you for your replies. I have a general question about Comsol. Am I able to stimulate something in animation in comsol? I was trying to put a magnet in magnetic field and trying to see if how the magnet is gonna to rotate/react to the magnetic field. But right now everything I do is stationary so am not able to really get much details about the motion. So i was wondering if there is anyting in comsol which I can actually do a animation. Thank you!
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check the forum, there should be some examples, and I have given some clues already in one of my replies today ;)
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Good luck
Ivar