Re: [ff3d-users] Inner wall definitions

[Stephane Del Pino]

Hello.

If I understand your question, you want to define different boundary 
conditions on a cylinder using the fictitious domain approach of ff3d?

To do so, define a long cylinder using the POVRay description:
it should have the radius of the cylinder that defines your geometry. Then 
define the embedding structured 3d mesh so that its intersection with the 
cylinder define your domain.

You can then use 2 different boundary conditions for the base and the top of 
the cylinder defining them using the background mesh and another one on the 
cylinder side.

for instance if the mesh is 'm', your cylinder axis is along the 'y' direction 
and its reference is <1,0,0>, and 'd' is the computational domain, you can do

        solve (u) in m by d
        {
          pde(u)
            -div(grad(u)) = f;
            u = 0 on M ymin; 
            u = 0 on <1,0,0>; 
            dnu(u) = 0 on M ymax;
        }

If you want ,you can also define completely your cylinder in POVRay using the 
intersection of a plane and a (POV) cylinder : then you have 2 different 
references ... I prefer the first approach.

Does this answers your question?

Best regards,
Stephane.