Elmer electrostatics FEM

[HoWil]

Do you mean ... https://forum.freecadweb.org/viewtopic. ... 30#p371807

[bernd]

The change has to be made in the 'Constants' section from

Code: Select all

...
Constants 
  Permittivity Of Vacuum = Real 8.8542e-21
End
...

to

Code: Select all

...
Constants 
  Permittivity Of Vacuum = 1 !Real 8.8542e-21
End
...

really ?!? I do not know elmer sif format. Why should there be still the old value? Or is the ! a comment marker?

[HoWil]

really ?!? I do not know elmer sif format. Why should there be still the old value? Or is the ! a comment marker?

Yes, ! is the comment marker (See page 14 in https://www.nic.funet.fi/pub/sci/physic ... Manual.pdf)

[bernd]

but than should not be the word integer before the 1 ?

[bernd]

or even better

Code: Select all

Real 1.0

[HoWil]

That is correct.
It works without but is totally unambigous with "Real".

[raback]

Hi

This is the list of specified keywords in Elmer:
https://github.com/ElmerCSC/elmerfem/bl ... R.KEYWORDS
Not all keywords have made it to the list and their type must be given by the user.

A Real valued keyword can be given value "1" even though it looks suspicious.

In the test the permittivity of vacuum was set to one to make it easier to compare to analytical expressions (with mesh resolution). If you emphasize more the physics here you could well use the real values.

-Peter

[bernd]

@HoWil:

Would you give https://github.com/berndhahnebach/FreeC ... rmittivity a try. Just add constand vacuumpermittivity obj. and change value in property editor. This should change the value in elmer sif file.

bernd

[bernd]

Should the two balls example from this topic be added to standard FreeCAD FEM examples ?

[HoWil]

Should the two balls example from this topic be added to standard FreeCAD FEM examples ?

If it works ... for sure
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