Dear Lahoussaine, This condition is a Fourier-Robin one. There is specific bricks in getfem for that (or of course you can just add the weak form with a linear term) on the considered boundary.
Best regards, Yves De: "Bourriche Lahoussaine" <lahoussaine.bourri...@etu.toulouse-inp.fr> À: "getfem-users" <getfem-users@nongnu.org> Envoyé: Mercredi 15 Juin 2022 10:56:32 Objet: Neumann condition Hello everybody; How i can implement Neumann boundary condition, who depends in the variable, for example for a variable T : k*n*nabla(T)=h(T-T_ext) and n the outward unit normal vector I want to apply this condition in the boundary of an object and not in the boundary of the whole geometrie BR Lahoussaine BOURRICHE