Von: firedrake-bounces@imperial.ac.uk [mailto:firedrake-bounces@imperial.ac.uk] Im Auftrag von David Ham
Gesendet: 23 September 2015 13:23
An: firedrake
Betreff: Re: [firedrake] Dirichlet BC on extruded mesh with discontinuous function space

 

I believe this functionality exists in Tuomas' branch. I'll be in Oregon next week and merging this is on my to do list.

 

[Buesing, Henrik] @David: Is there a way to obtain this branch? And a small example how to set the function value of the boundary cells?


Thank you!

Henrik

 

 

On Wed, 23 Sep 2015 at 11:34 Buesing, Henrik <HBuesing@eonerc.rwth-aachen.de> wrote:

 

Von: firedrake-bounces@imperial.ac.uk [mailto:firedrake-bounces@imperial.ac.uk] Im Auftrag von Andrew McRae
Gesendet: 23 September 2015 12:16


An: firedrake@imperial.ac.uk
Betreff: Re: [firedrake] Dirichlet BC on extruded mesh with discontinuous function space

 

Yes, but it should still be possible to set the value of the function in those cells.  Didn't Tuomas make some progress on this functionality?  I don't remember what the current status is.

[Buesing, Henrik] That would be nice. Then I can just prescribe the right value at those cells. If this is enforced during the KSP, SNES solves everything should be fine.

As a workaround, Miklos's suggestion may suffice.

On 23 September 2015 at 11:09, Miklos Homolya <m.homolya14@imperial.ac.uk> wrote:

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?

 

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

------------------------------------------------------

Mathieustr. 10            |    Tel +49 (0)241 80 49907

52074 Aachen, Germany     |    Fax +49 (0)241 80 49889

------------------------------------------------------

------------------------------------------------------

 

_______________________________________________
firedrake mailing list
firedrake@imperial.ac.uk
https://mailman.ic.ac.uk/mailman/listinfo/firedrake