Troubles calculating harmonic magnetic fields

[wiesi]

Solving stationary magnetic fields works fine so far, but now I need to extend my investigations to harmonic analysis to incorporate eddy currents and skin effect (using WhitneyAVHarmonicSolver). I'm not really sure if Elmer can do this.

I used the mgdyn_harmonic testcase as a starting point. Up to now, Im only trying to simulate a straight conductor with rectangular cross section in which I want to see the skin effect when I increase the frequency.

My problems so far are:
1)
For static magnetic fields, I used the StatCurrent solver to calculate the current density which I used as input for the magnetic field solver. In the new case this is, of course, not possible, because the the magnetic field and current distribution interact, so I have to tell the HarmonicSolver to do this.
I tried this by prescribing the electric potential at the two end of the conductor. (I've attached my current .sif file)

The potential distribution looks OK (http://imagebin.org/162274), going linearly from 0 to 10. The current density doesn't look that good, I can't explain the quite big variations (http://imagebin.org/162275) (but I the mesh isn't very good). The average is about 180 (should be about 200), so it isn't completely wrong.
But the resulting magnetic field doesn't make any sense, it just looks random (http://imagebin.org/162276). (The vectors show the magnitude of the magnetic field strength).

2)
ElmerSolver outputs the following:

Code: Select all

MAIN: -------------------------------------
MAIN:  Steady state iteration:            1
MAIN: -------------------------------------
MAIN:
Mainutils: No Passive element boundary found
DefUtils::DefaultDirichletBCs: Setting Dirichlet boundary conditions
DefUtils::DefaultDirichletBCs: Dirichlet boundary conditions set
SolveSystem: Solution trivially zero!
DefUtils::DefaultDirichletBCs: Setting Dirichlet boundary conditions

The "Solution trivially zero!" tells me that there may be something wrong. (If I only knew what.)
and

Code: Select all

Mainutils: No Passive element boundary found
GetAngularFrequency: Angular frequency could not be determined!

Those two messages appear with the original mgdyn_harmonic case, too. I don't know what the first means, but the second looks like a problem.

Thank you in advance, wiesi