[Libmesh-users] Implementation question

[Kevin E. <kel...@am...>]

Hi All,

I am getting to the point where I understand C++ well enough to use 
libmesh and I would like to do so, abandoning my own ancient monolithic 
"c" based code.  The problem that I would like to first tackle is 
basically a nonlinear transient reaction diffusion problem.  For this, 
the examples supplied with libmesh are very relevant.  However, I have 
an additional unknown "u" that is assumed to be a lumped parameter, that 
is, it is constant throughout the spatial domain but is a function of 
time.  It is couple to the rest of the unknowns through a surface 
integral along one edge.  So I have,

 1:  dc/dt = div(D(c)*grad(c)) + f(c)
 2:  du/dt = int_s D(c)*grad(c).n ds
 3:  c = f(u) on s                                   

In my own "crappy" code, I introduce one extra local node in each 
element which are all linked to one extra global unknown, which 
represents "u".  I enforce the Dirichlet BC using a penalty approach and 
I build eq. 2 as I go. 

Is there a proper way for doing something similar in libmesh and might 
anyone have a "libmesh" example that is close that they could share?

-- 
                              .*.
       Kevin R.J. Ellwood     /V\
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