[Getdp] Re: (no subject)

[Johan Gyselinck]

janvrot at infolink.com.br wrote:

> > You just have to replace dhdb[] and h[] by dbdh[] and b[]
> > respectively. This was already partly prepared in the file with the
> > tables I sent you a while ago.
> >
>
> Sorry, but I didn't get it.

I was referring to this:

  Jan_mu_h2  = ListAlt[Jan_h2, Jan_mu] ;
  mu_Jan[] = InterpolationAkima[$1]{List[Jan_mu_h2]} ;
  dmudh2_Jan[] = dInterpolationAkima[$1]{List[Jan_mu_h2]} ;
  b_Jan[] = mu_Jan[(SquNorm[$1#3])] * #3 ;
  dbdh_Jan[] = TensorDiag[1,1,1] * mu_Jan[SquNorm[$1#1]#2] +
2*dmudh2_Jan[#2] * SquDyadicProduct[#1]  ;

which was in the file I sent you, wasn't it?

>
> So, is this correct for the scalar magnetic potential in a case where
> there are no current loops?
>
> Formulation {
>   { Name MagSta_phi_nl; Type FemEquation;
>     Quantity {
>       { Name phi; Type Local; NameOfSpace Hgrad_phi; }
>     }
>     Equation {
>       Galerkin { [ - mu[] * Dof{d phi} , {d phi} ];
>                  In NonSteel; Jacobian MyJac; Integration MyInt; }
>
>       Galerkin { JacNL[ dbdh[{d phi}] * Dof{d phi} , {d phi} ] ;
>                  In Steel ; Jacobian MyJac ; Integration MyInt ; }
>
>       Galerkin { [ b[{d phi}] , {d phi} ]  ;
>                 In Steel ; Jacobian MyJac ; Integration MyInt ; }
>
>       Galerkin { [ - mu[] * hc[] , {d phi} ];
>                  In Magnet; Jacobian MyJac; Integration MyInt; }
>     }
>   }
> }

You should add a minus sign to the two terms in the middle!  (Remember
that in the linear case, dbdh = mu !)
Besides that it looks ok.


Johan

PS For those trying to solve a 3D magnetostatic problem with an imposed
current density using GetDP, maybe you should consider the possibility of
modelling the excitation (in an approximate way) by means of one or
several permanent magnets.  In that case, the formulation is very simple.

--
Dr. ir. Johan Gyselinck
University of Liege
Dept. of Electrical Engineering (ELAP), Institut Montefiore
Campus du Sart Tilman, Parking P32, Bâtiment B28, B-4000 LIEGE, Belgique
phone: +32-4-3663732 -- fax: +32-4-3662910 -- http://elap.montefiore.ulg.ac.be/


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