[Getdp] How to define Robin boundary conditions

Thomas Ward tomwardathome at googlemail.com
Fri Oct 16 09:25:14 CEST 2009


many thanks Lars,
yes it is normal to the boundary
your example helped a lot, especially since you had shown the problem
equation alongside the getdp code, it helped me to decipher the getdp
syntax.

so I think I need


Formulation {
  { Name f1 ; Type FemEquation ;
    Quantity {
      { Name phi ; Type Local ; NameOfSpace fs1 ; }
    }
    Equation {
      Galerkin { [ Dof{d phi} , {d phi} ] ; In Omega ; Jacobian Vol ;
Integration Int ; }
      Galerkin { [ k*Dof{d phi} , {phi} ] ; In Top ; Jacobian Vol ;
Integration Int ; }
    }
  }
}

regards

Tom


On Fri, Oct 16, 2009 at 7:27 AM, Lars Rindorf
<Lars.Rindorf at teknologisk.dk>wrote:

>  Hi Tom
>
>
>
>
>
> Is the spatial derivative normal or perpendicular to the 3D cube boundary?
> If it is perpendicular, you can see the scatpar example. That is similar.
>
>
>
> Kr, Lars
>
>
>
> *Fra:* getdp-bounces at ace20.montefiore.ulg.ac.be [mailto:
> getdp-bounces at ace20.montefiore.ulg.ac.be] *På vegne af *Thomas Ward
> *Sendt:* 16. oktober 2009 08:20
> *Til:* getdp at geuz.org
> *Emne:* Re: [Getdp] How to define Robin boundary conditions
>
>
>
> oops that should have read ".... thanks to Christophe ..... "!
>
>  On Thu, Oct 15, 2009 at 5:01 PM, Thomas Ward <
> tomwardathome at googlemail.com> wrote:
>
>
> Probably a simple question but I can't find the answer in the examples of
> the wiki or searching the list.
>
> I am trying to define a Robin type boundary condition for the Laplace
> equation on a cube
>
> dphi/dz+constant*phi=0 on one face
>
> I think the weak form of this is
> integral_over_face(test_function * trial_function*constant) =0
>
> can someone point me to an example of how to write this in the .pro file?
> thanks
>
> and thanks to Christian for his public spiritedness over many years by the
> look of the archives.
>
> Tom Ward
>
>
>
>
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