Hello,
I'm trying to write a code in deal.II to solve a moving boundary problem, where
the boundary moves according to the velocity field $\mathbf{v}$. After solving
at each timestep, I want to interpolate the "old_solution" onto the new grid.
However, I am unsure about how to go about this. I can move the mesh as in
step-18, but this does not include interpolation of the solution? I was
thinking of using FEFieldFunction, but triangulation2 needs to be entirely
included within triangulation1, but if the boundary is moving, this may not be
the case.
I tried using something like
------------------------------------------------------------------------------------------------------------------------------------------
BlockVector<double> x_sol = solution;
SolutionTransfer<dim, BlockVector<double> > solution_transfer(dof_handler);
for (typename DoFHandler<dim>::active_cell_iterator
cell = dof_handler.begin_active ();
cell != dof_handler.end(); ++cell)
{
for (unsigned int v=0; v<GeometryInfo<dim>::vertices_per_cell; ++v)
{
if (vertex_touched[cell->vertex_index(v)] == false)
{
vertex_touched[cell->vertex_index(v)] = true;
Point<dim> vertex_displacement;
for (unsigned int d=0; d<dim; ++d)
{
vertex_displacement[d] =
time_step*solution(cell->vertex_dof_index(v,d));
}
cell->vertex(v) += vertex_displacement;
}
}
}
solution_transfer.interpolate(x_sol, solution);
--------------------------------------------------------------------------------------------------------------------
but even if I redistributed dofs etc, I still get the error
void dealii::SolutionTransfer<dim, VECTOR, DH>::interpolate(const VECTOR&,
VECTOR&) const [with int dim = 2, VECTOR = dealii::BlockVector<double>, DH =
dealii::DoFHandler<2>]
The violated condition was:
in.size()==n_dofs_old
The name and call sequence of the exception was:
ExcDimensionMismatch(in.size(), n_dofs_old)
Additional Information:
Dimension 3202 not equal to 0
which I don't really understand, as my "n_dofs_old" should have size 3202 as
well, as the mesh is just moved! May be I have missed something quite simple.
Any help would be greatly appreciated :)
Thanks and have a good weekend!
Katie
Katie Leonard
DPhil student in Computational Biology,
The University of Oxford.
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