> Up until now the geometry of the needle that acts as an antenna during the
> ablation, was simply subtracted from the domain and thus prescribing the
> boundary condition (which is setting a certain voltage on the electrode
> boundary) was not a problem. But excluding the needle from the domain is
> obviously not a correct way of calculating EM field. Therefore right now
> I'm trying to use multiple materials for 'liver tissue' and 'electrode'. It
> is not a problem to create a UCD file such that these subdomains can be
> distinguished within deal.ii code. However so far I didn't find a way to
> pass the information about the parts of inter-material boundaries and/or
> nodes at these parts of boundaries to deal.ii. The boundary marking doesn't
> fit with deal.ii because it throws exception stating that internal quads
> cannot be boundaries.
Yes, we identify internal faces by using a special "boundary" indicator
number. In essence, internal faces and edges can neither have boundary nor
material indicators.
> I need this information to set the prescribed voltage
> values at these nodes/boundaries (by the way - do I understand correctly
> that for nodes within domain such constrains should be done using
> ConstraintMatrix objects?).
Yes, this would probably work, assuming your model remains well posed.
> Is there any better way of finding these nodes other than creating a
> special material id and then searching for nodes that belong to cells with
> a certain combination of material id's?
That would be one way, or you can identify these faces by checking whether the
adjacent cells have boundary indicators that correspond to tissue and
electrode domains. Like this:
for (cell=....)
for (face=0...GeometryInfo<dim>::faces_per_cell; ...)
if (cell->at_boundary(f) == false
&&
cell->material_id() == tissue_id
&&
cell->neighbor(f)->material_id() == antenna_id)
... found an interesting face ...
Maybe that would help.
Best
Wolfgang
-------------------------------------------------------------------------
Wolfgang Bangerth email: [email protected]
www: http://www.math.tamu.edu/~bangerth/
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