Dear Sebastien, No of course. For an order two isotropic pde, a homogeneous Neumann condition reads as dU/dN = 0 This condition does not add any term to the weak formulation. So you do not have to add anything to the model.
Yves. On mercredi 7 avril 2010, sébastien janas wrote: > Dear Yves, > > When we prescribe a zero neumann condition, we impose that the product > between the unknown and the normal vector is equal to zero, is it equal > to assume that the product bewteen the GRADIENT of the unknown and the > normal vector is equal to zero ? > > In other words, you advise me to do > > n x U = 0 > > and I want to do > > dU/dn = 0 > > is it equal ? > > Best regards, > > Sébastien > > Le mercredi 07 avril 2010 à 21:12 +0200, Renard Yves a écrit : > > Dear Sebastien, > > > > If you have to prescribe a zero Neumann condition to your unknown > > (assuming that it is an order two isotropic pde), you > > do not have to add anything to your model. This is somehow a default > > boundary condition as it add nothing to the weak formulation. > > > > Yves. > > > > sébastien janas <[email protected]> a écrit : > > > hi, > > > > > > I am using the python interface of getfem. I want to impose the normal > > > derivative of my unknow to zero at the boundary, but it seems that the > > > model method "add.normal_derivative_source_term" don't exist, is it > > > correct ? If yes, what's the best way to impose such a condition on a > > > model ? > > > > > > Thanks a lot for your help, > > > > > > Sébastien > > > > > > > > > _______________________________________________ > > > Getfem-users mailing list > > > [email protected] > > > https://mail.gna.org/listinfo/getfem-users -- Yves Renard ([email protected]) tel : (33) 04.72.43.87.08 Pole de Mathematiques, INSA-Lyon fax : (33) 04.72.43.85.29 20, rue Albert Einstein 69621 Villeurbanne Cedex, FRANCE http://math.univ-lyon1.fr/~renard --------- _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
