[Getdp] Magnetic Force 3

[Jasper]

Hi,

I've used a scalar potential to calculate the field in a 3D
magnetostatics problem. Looking at the fields the results look
correct. Now I would like to calculate the force on a object due to
this magnetic field.
>From what I can gather from the mailing list several people have
already done this before, but I have yet to find any examples. It
appears the force can be calculated in three different ways:

- Take the B-field, and compute 1/mu0 * B x ( Curl B ) over the
volume. This is probably easiest achieved in PostProcessing or Gmsh,
but somehow the Curl B of my field in Gmsh returns zero...
- Compute the Maxwell Stress Tensor using the B-field, and integrate
it over the surface of the object. This is probably best performed in
PostProcessing, but I'm at loss on how to go from the B-field in the
element volumes to the field at the surface of the object.
- Using Virtual Works. No idea how to do that, but it probably
involves small displacements :-)

If anybody can show me some examples of computing these quantities it
would be very much appreciated. Thanks in advance for your help. Best
regards,

Jasper