[Getdp] Re: getdp: conductivity, el. quasistatical approx.

Christophe Geuzaine Christophe.Geuzaine at ulg.ac.be
Wed Aug 1 16:09:49 CEST 2001


Samuel Kvasnica wrote:
> 
> > computed in the first). You could also couple the formulations through
> > weak boundary conditions (by simply referencing a quantity from one
> > formulation into the other and writing the appropriate surface term to
> > integrate). But I'm still not convinced that this coupling is the thing
> > to do in your case. I think you should first be sure of the hypotheses
> > you make, before attempting to solve anything...
> 
> Hmm, well, but think about design of high voltage power device where you
> first compute potentials and then field strength around to optimize the circuit geometry / select right
> insulator to avoid breakdown. This problem has no connection with the secont electrodynamic case I need also to
> solve.
> 
> >
> >
> > >
> > > > If displacement and conduction currents are of the same order of
> > > > magnitude, you end up with the so-called electrodynamic model:
> > > >
> > > >      Equation {
> > > >        Galerkin { DtDof [ epsr[] * Dof{d v} , {d v} ] ;
> >
> > Copy/paste mistake here: should be eps0*epsr[]!
> 
> Yes, right, but I'm getting the same sort of results after correction.
> 
> > > ok, that sounds good. I tried it, solve converges but at the and I get strange results displayed in gmsh -
> > > potential lines
> > > are dashed and it looks like there were missing mesh elements when I try to visualize them in option dialog of
> > > potential.
> >
> > Don't forget to rerun the preprocessing before solving when you change
> > the type of the system you solve : the unknows are different (and twice
> > as many).
> 
> Of course, I do always rerun the preprocessor  when I change the geometry or model. I can't find the mistake,
> if I coment out the Dt part and frequency option everything looks ok in electrostat. approx. After I use frequency
> option, I'm getting
> that strange results. Is there something else I have to change except the formulation and Frequency option ?
> 

No, that should be enough. A stupid question : there was a bug in
version 0.82 of getdp for the binary Gmsh output format. Do you use
version 0.83?

--
Christophe Geuzaine

Tel: 32 (0) 4 366 37 10    http://geuz.org
Fax: 32 (0) 4 366 29 10    mailto:Christophe.Geuzaine at ulg.ac.be



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