Hello Tim,


Let your mesh object be called mesh, in this case FacetNormal(mesh) is the form expression that I think you need. Generally, one


n = FacetNormal(mesh)


and then just uses n in the form.


Cheers,

Miklos


From: firedrake-bounces@imperial.ac.uk <firedrake-bounces@imperial.ac.uk> on behalf of Dodwell, Timothy <T.Dodwell@exeter.ac.uk>
Sent: 25 August 2017 13:08:13
To: firedrake
Subject: [firedrake] Normal to curved surface
 
Hi all,

New to firedrake, I am building a test problem for a new PhD which is poro-elastic consolidation of a sphere, I want to apply a pressure boundary (Neumann) condition to a curved surface.

I.e \int (\sigma \dot n) \dot v\; ds

Where n is the normal vector to the surface ds.

Is there a function normal() which returns it for me. A look a documentation doesn’t look promising!

Cheers

Tim


Dr Tim Dodwell
Senior Lecturer in Engineering Mathematics
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University of Exeter
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