[Getdp] Microwave Example, 3D, sources

Daryl Van Vorst dvpub at telus.net
Sat Feb 3 23:08:45 CET 2007


Hi,

I'm trying to get the MWE example from the wiki to work for a simple 3D
problem (and then will hopefully apply it to a more complex problem once
things things are clear to me).

Some simple questions to help me figure out what I'm misunderstanding:
(Any helpful comments would be greatly appreciated)

1. Can I impose a time varying volume current (J_s[]) in a small length
of the centre conductor? This would be the only source term. I have
tried this, but am unable to get any meaningful results. I'll put
details in another e-mail if this is something that should work.

2. There is a slight difference between MW_e_2Dt and MW_e_3Dt.    

The 2D one has:
 Operation { 
      InitSolution[A] ;
      InitSolution[A] ;
      TimeLoopNewmark[t_min,t_max,dt,0.25,0.5] {
        Generate[A] ; Solve[A] ; 
        Test[ SaveFct[] ] { SaveSolution[A] ; }
      } 
    } 

The 3D one has:
    Operation { 
      InitSolution[A] ; SaveSolution[A] ;
      TimeLoopNewmark[t_min,t_max,dt,0.25,0.5] {
        Generate[A] ; Solve[A] ; 
        Test[SaveFct[]] { SaveSolution[A] ; }
      } 
    }

For the 3D case getdp complains: "Not enough initial solutions for
TimeLoopNewmark". So I presume that either I'm missing a crucial step in
setting up the problem, or this should be changed to be similar to the
2D case. Which is right?

3. Can I impose an electric field on a surface (in the xy-plane) with
something like:?

Constraint {{Name e; case { { Region source ; Value Vector [1.,0,0] ;
TimeFunction TimeFct[];} } } }

Doing this does not appear to result in the desired field. It does
appear to impose something on the surface, but not an x-directed
electric field of magnitude 1. (I've also tried a radially directed
field which is more appropriate for a coax.)

4. What kind of resolution should I be using for a transient problem
with a time varying J_s[]? And would this be a different resolution for
a time varying field constraint (like above)?

Thanks,

Daryl.