# [Getdp] (no subject)

Ruth Vazquez Sabariego ruth.sabariego at kuleuven.be
Sat May 25 08:39:49 CEST 2019

```Dear Anton,

You should use the Maxwell stress tensor. You will find all you need in:
https://gitlab.onelab.info/doc/tutorials/wikis/Magnetic-forces

It is a 3d problem with a curl-curl equation, so you need the gauging for being able to solve the problem with a direct solver.
BTW it is not correct in your files. You are using a tree-cotree gauge that should be defined in the whole domain. The tree should start on the surfaces where you already have a condition. An explanation on the gauging is also available at the example above.

Best regards,
Ruth Sabariego

PS: Please send your questions to the list, it can be useful to other people.

—
Prof. Ruth V. Sabariego
KU Leuven, Dept. Electrical Engineering ESAT/Electa, EnergyVille
http://www.esat.kuleuven.be/electa
http://www.energyville.be

On 24 May 2019, at 21:49, Panteleev, Anton <anton.panteleev at haw-hamburg.de<mailto:anton.panteleev at haw-hamburg.de>> wrote:

Dear Professor Sabariego,

I program the magnetic field of the actuator and want to calculate the forces acting on the moving part, in my example it is Region [{8000}];
Could you tell me which example from ONELAB should I take: Magnetometer or Magnets? If I take the example of a Magnetometer, can I use GaugeCondition_a instead of ElectricScalarPotential ...? And if I take the example of Magnets, then in my example there is no Maxwell stress tensor.
Please tell me how I better calculate the forces arising in the magnetic field for my example.

P.S. I attached two files to this letter: geo. and pro. with my example

best regards
Anton Panteleev

<P5.geo><P5.pro>

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