[Getdp] Thin layers

[Stephane Hole]

Dear Christophe,

I am interested in using surfaces instead of volumes for the simulation
of thin layers as I hope it would reduce drastically the calculation
times since less volume elements are generated.

I saw in your PhD thesis that a weak formulation (for instance 3.14) can
be used for this purpose but I don't know how write it in GetDP.

Can you tell me if it is possible to use such formulation, and if yes
how to write it. 

Thank you,
Stephane.