Elmer Discussion Forum

Hi,
I am new to ELMER. Trying to understand how elmer works.
I was trying to recreate Tutorial 7 (magnetic field induced by harmonic current in a wire) using elmer and paraview. I just noticed that while creating boundary condition, documents says use "MgDyn" tab but i could not see the options ("AV im e") in this tab. so i used "MgHram" option to create the boundary conditions .
Now i run the model and got some results but not same as presented in tutorial 7 of "ElmerTutorial" document.
Created files are attached here. Please help.

Hi

There was a typo in the tutorial and you correctly corrected that by using MgDynHarm menu. So for this I don't think you need any more help.

-Peter

Hello Peter,

I appreciate your response but something is wrong at my side.
I ran this model many times and always have same results. when I post the .vtu file in paraview for post processing, It shows magnetic field value range as 0 to 1e-38. Joule heating range as 0 to 1e-38 and voltage as 0.01 volt.

I am attaching all the files (analysis and images from paraview) please suggest me where i am wrong and what should I do to correct it.

I am getting same magnetic filed strength for Horse shoe (tutorial 8) and for Graphite crucible (tutorial 15) as well. So I believe i am making same mistake.

Please help me

Kind regards

Hi,

I have never done a magnetic simulation, so just a trivial observation: In your sif file, you seem to set a voltage of 0.01 V as boundary condition. Is that on purpose? It concides with your voltage result, so there may be some correlation...?
More generally (and just as trivial, but you never know ), are you sure that you exactly reproduced the settings of the tutorials? Did you compare with the contents of the tutorials files?

HTH,
Matthias

Hi Matthias,

Thank for your reply. You are right about voltage as boundary condition.
I followed the tutorial its about potential difference of 1V/M over the wire and wanted to know the magnetic field strength around the wire.
So the boundary condition is correct.

It is possible that i am not using Paraview correctly or did not get output for paraview. I might have missed some option to select while generating output (but followed all the instruction given in tutorial). As i mentioned i found same results for all 3 tutorials (related to magnetic field analysis). that itself says that i am making some mistake. Even the tutorial 8 (Horseshoe) I can see the results in Elmer 8.2 (ELMER 8.2 allow post processing itself) and I can see the results as produced in tutorial.

I am getting Norm of the solution 0.36798 for horseshoe (tutorial 8, as mentioned in tutorial). so don't see any problem in model and running it. i think problem is getting correct results for PARAVIEW.
Please help

Hi,

I`ve got some problems with this tutorial too, although I can´t even get any results out of the Solver.
I am using Elmer on a Windows 10 machine. I´ve tried to reproduce this tutorial step by step using Elmer 8.2, and the latest Elmer 8.3 version.
Just by reproducing the tutorial I get the Error message:

ERROR:: Model Input:
ERROR:: Model Input: Unknown specifier: [0]
ERROR:: Model Input: In section: [boundary condition 1]
ERROR:: Model Input: For property name:[av re {e} 1]

After editing the boundary conditions with the keyword Real this error disappears

AV re {e} 1 = 0
AV re {e} 2 =Real 0
AV im = 0
AV im {e} 1 =Real 0
AV im {e} 2 =Real 0
AV re = 0.01
...

But now I get this error message:

ERROR:: MagnetoDynamicsCalcFields: potential variable not available

I´ve tried to start the solver without the MgDynPost Solver, and also defined the correct variable in the MgHarm solver.
At this point the solver starts, but without a result. The log says: SolveSystem: Solution trivially zero!

I think I´ve overlooked a fundamental step here.
Can someone give me a hint were the problem lies?

Thank you in advance!

Hi,

difficult to say without seeing your sif file. You could compare it with the one on the tutorials files to see where there are differences.

Matthias

Hi,

I will post the sif file in an few hours.
Can you tell me where to find the complete files for this tutorial?
I've downloaded the .zip with the GUItutorials from csc, and also searched on GitHub, but I could find the .sif file for this specific tutorial.

Hi,

you are right, there don't seem to be tutorials files for that one.
So just post your sif file, I will have a quick look.

Matthias

Hi

Unfortunately the projects should be redone and distributed. However, this case is almost as such available as test case: mgdyn_harmonic_wire.

-Peter