dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Mon, Apr 19, 2010 at 11:43:05AM +0200, Patrick Riesen wrote:
> Anders Logg wrote:
> >On Mon, Apr 19, 2010 at 10:39:26AM +0200, Patrick Riesen wrote:
> >>hello,
> >>
> >>I possibly want to implement a free surface problem with my dolfin
> >>code using the dolfin ALE functionality. dolfin can do the automatic
> >>updating of the mesh nodes or else shift the nodes by a
> >>user-supplied displacement function.
> >>
> >>in the automatic updating, the vertex-displacements are
> >>'method-supplied' and not accessible, but i need to have them in
> >>some displacement function  in order to compute correct convective
> >>velocities at all theeuler/ale/lagrange dofs.
> >>
> >>i can get the displacements at the mesh vertices from comparing old
> >>(not yet moved) and new (moved) mesh, but what's a good way to
> >>generate a displacement function in a desired functionspace out of
> >>those vertex-values?
> >
> >What is you input?
> >
> >Is it displacement on the boundary? Then you can just send in the
> >displaced boundary as argument to mesh.move().
> >
> i define how the free boundary part will be handled/displaced, and
> then i use dolfin ALE to automatically adjust the interior nodes.
>
> but then don't i need the displacements applied by dolfin at the
> interior nodes to keep track of the relative displacement between
> mesh and fluid everywhere in the domain (and my equations)?

What if you just make a copy of the mesh (or just its coordinates)
before you call DOLFIN to move the interior nodes? Then you can
compute the difference after.

--
Anders

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