Dear GetFem++ users,
I am trying to solve a system concerning blood flow in a tissue and a blood vessel, so I have a coupled 3D (tissue)-1D(vessel) problem, using Matlab interface.
My unknowns are velocity u and pressure p either in the tissue and in the vessel, we will call them ut, pt, uv, pv. The first one is a 3D vector field, while the other three are scalar fields.
Clearly they are defined on different functional spaces, and so their test functions.
I managed to obtain some of the sub-matrices contained in the complete tangent matrix, but when I have to evaluate the interpolation matrix on the boundary of the vessel I find myself stuck.
In particular I need to evaluate the interpolation matrix on the boundary of the vessel, that is composed by the surrounding points of each node of the vessel.
Now my questions are:
1) How can i define a 1D region in a 3D domain as a set of points and not of convexes nor faces?
2) Since my vessel is a 1D line, how can I define for each node the "ring" of the surrounding points that will be useful to define my interpolation matrix?
OmegaM; %mesh
Pts; %List of pts that compose the vessel
s1 = gf_slice('points', OmegaM, Pts');
CVids1 = gf_slice_get(s1, 'cvs');
CVFIDs = gf_mesh_get(OmegaM, 'outer faces', CVids1); %faces
gf_mesh_set(OmegaM, 'region', 33, CVFIDs); %"boundary pipe" around the vessel.
Thank you very much for your attention,
Best regards,
Davide