Von: firedrake-bounces@imperial.ac.uk [mailto:firedrake-bounces@imperial.ac.uk] Im Auftrag von Miklos Homolya
Gesendet: 23 September 2015 12:10
An: firedrake@imperial.ac.uk
Betreff: Re: [firedrake] Dirichlet BC on extruded mesh with discontinuous function space

 

Dear Henrik,

 

You’ve got a DG0 space, i.e. all your nodes are in the cell centres. Neither topologically nor geometrically have you any nodes on the boundary faces.

 

Maybe you want to impose your BC weakly?


[Buesing, Henrik] Could you explain a little, how I can impose Dirichlet BC in this way? Thank you!

Henrik

 

 

Regards,

Miklos

 

On 23 Sep 2015, at 12:05, Buesing, Henrik <HBuesing@eonerc.rwth-aachen.de> wrote:

 

Dear Firedrakers,

 

I’m constructing a DG space on an extruded mesh.

 

meshbase = RectangleMesh(Nx, Ny, Lx, Ly, quadrilateral=True)
mesh = ExtrudedMesh(meshbase, Nz, Delta_z)
horiz_elt = FiniteElement("DG", quadrilateral, 0)
vert_elt = FiniteElement("DG", interval, 0)
elt = OuterProductElement(horiz_elt, vert_elt)

DG = FunctionSpace(mesh, elt)

W=DG*DG

 

Now I would like to impose Dirchlet BC on one of the boundaries.

I tried

bc0 = DirichletBC(W.sub(0), Expression("1.0e7"), 2,method="geometric")

 

and get a

 

ValueError: Geometric boundary conditions are not yet supported on extruded meshes

 

Using the standard topological way, seems to have no effect at all.

 

Is there a way around this? I would be fine with fixing the value on the most outer cell layer, if that is possible…

 

Henrik

 

 

 

 

 

--

Dipl.-Math. Henrik Büsing

Institute for Applied Geophysics and Geothermal Energy

E.ON Energy Research Center

RWTH Aachen University

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