DOLFIN

Prescribing boundary conditions in boundary-normal direction

Asked by Miklos Galamb

Hi,

I was wondering what the best practice is for prescribing boundary conditions in the direction of the boundary-normal. I would need this e.g. for prescribing a slip-boundary in a fluid problem or a sliding-support for a structural problem.

All tipps are greatly appreciated,

Miklos

Question information

Language:
English Edit question
Status:
Solved
For:
DOLFIN Edit question
Assignee:
No assignee Edit question
Solved by:
Anders Logg
Solved:
Last query:
Last reply:
Revision history for this message
Best Anders Logg (logg) said : 		#1

On Wed, Jun 29, 2011 at 09:55:56AM -0000, Miklos Galamb wrote:
> New question #163136 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/163136
>
> Hi,
>
> I was wondering what the best practice is for prescribing boundary conditions in the direction of the boundary-normal. I would need this e.g. for prescribing a slip-boundary in a fluid problem or a sliding-support for a structural problem.
>
> All tipps are greatly appreciated,

The only easy way to do this at the moment is to choose the geometry
such that you can set either the x- or y-component to zero. This can
be done by

 bc = DirichletBC(V.sub(0), 0.0, boundary) # x-component
 bc = DirichletBC(V.sub(1), 0.0, boundary) # y-component

At some point, we might consider adding a SlipBoundaryCondition class.

--
Anders

Revision history for this message
Miklos Galamb (miklosgalamb) said : 		#2

Hi Anders,

Thank you for the lightning fast answer, that solved my question!

Miklos

Revision history for this message
Miklos Galamb (miklosgalamb) said : 		#3

Thanks Anders Logg, that solved my question.