[Getdp] Magnetic Field Lines From 3D Magnetic Field?

Kubicek Bernhard Bernhard.Kubicek at arsenal.ac.at
Tue Apr 10 15:38:39 CEST 2007


Hello Alain,

Maybe the solution to your problem is this:
Output the mangetic field (vectorial),
Load into Gmsh,
rightclick the appropriate view (e.g. 0), 
select plugins->stream lines
Ajust the 3 points, so that the span the area which shall be source for the streamlines.
A good starting point for dt is (physical dimension of your geometry)/(approx norm max field )/10
Iview and dView should both have the view-nr. of your vectorial magnetic field.


However, what is still to be found is a way of showing "real" field lines, which are also more dense if there is a higher flux. However, most num elec. dynamic software is said to not do this.
In 2d, there are rumours that one gets them as iso-lines of the z-component of the mag. vec. potential. Here, tree gauge may be not very helpful, as the gauge condition is not very physical ..

Hope this helps!

nice greetings, 
 bernhard

-----Ursprüngliche Nachricht-----
Von: getdp-bounces at geuz.org [mailto:getdp-bounces at geuz.org] Im Auftrag von Alain
Gesendet: Dienstag, 10. April 2007 15:13
An: getdp at geuz.org
Betreff: [Getdp] Magnetic Field Lines From 3D Magnetic Field?


Dear Users:
In magnetostatic 2D examples, it is easy to look at the magnetic lines 
which lines up quite nicely with the magnetic field vector simply by 
setting Iso-values as graphic output on the "a scalar potential" view.
    However, for 3D magnetic field, as I mentioned before, it is not so 
easy. First, the "3D scalar potential" does not seem to be as accurate 
as in the 2D case and cannot be used. Second, using only the 3D magnetic 
field vector as base view, it does not seem to be possible to ever see 
these field lines in any 2D plane extraction schemes e.g.   cut plane , 
cut grid , extract ,skin  etc. The only Iso-lines views are always 
perpendicular to the field lines.

    What is the proper way to do this? This may be a Gmsh question but 
maybe I am not using the proper field solution in Getdp.
     I would really like to be able to see these lines.
     Maybe  it is not possible to do. You can use the "ring_magnet.pro" 
to see what I mean.
Thanks,
Alain Martin
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