dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Jan 15, 2008 at 08:33:07AM +0100, Murtazo Nazarov wrote:
> > Related question for both incompressible flow and elasticity
> > problems.  Suppose I have a plane of symmetry that will allow me to
> > reduce my computational domain.  If
> >
> > \sigma_ij
> >
> > is the relevant stress tensor, then I will have that
> >
> > t^k_i \sigma_ij n_j = 0
> 
> Ones you have tangential and normal vectors, you can include this as a
> boundary term to the ffc form?

FFC/DOLFIN only have built-in facet normals (FacetNormal). There is no
FacetTangent but it would be easy to add (if we just define what we
mean by the tangents on a face of a tetrahedron).

-- 
Anders


> >
> > where t^k is the k-th tangential vector of the local geometry.
> > Physically, this is vanishing shear stress.  This is in addition to
> > the condition
> >
> > u_i n_i = 0
> >
> > for no normal flow (the slip condition).
> >
> > Any thoughts on implementing the vanishing shear stress condition?
> >
> > -gideon
> >
> > On Jan 14, 2008, at 2:57 PM, Murtazo Nazarov wrote:
> >
> >>> Is there an obvious high level way to implement normal flow type
> >>> boundary conditions or symmetry type boundary conditions?
> >>>
> >>> -gideon
> >>>
> >>
> >> If you mean slip boundary condition which for normal velocity, it is
> >> already implemented and soon will be available with UNICORN.
> >>
> >> The slip with friction is also implemented.
> >>
> >> /murtazo
> >>
> >>> _______________________________________________
> >>> DOLFIN-dev mailing list
> >>> DOLFIN-dev@xxxxxxxxxx
> >>> http://www.fenics.org/mailman/listinfo/dolfin-dev
> >>>
> >>
> >>
> >
> > _______________________________________________
> > DOLFIN-dev mailing list
> > DOLFIN-dev@xxxxxxxxxx
> > http://www.fenics.org/mailman/listinfo/dolfin-dev
> >
> 
> 
> _______________________________________________
> DOLFIN-dev mailing list
> DOLFIN-dev@xxxxxxxxxx
> http://www.fenics.org/mailman/listinfo/dolfin-dev