[Getfem-users] Neumann Boundary Condition Normal to Level-Set Boundary

[Patrick Schmidt]

Dear Getfem users,

I am new to getFem and made my way through the demo_crack.py file in order to use the implemented XFEM formulation.

Now I would like to set up a boundary value problem where a pressure acts orthogonal to the surface of the discontinuity. I tried to find some way in order to apply source terms orthogonal on the surface of the discontinuity. In terms of the boundary condition that's as far as I got:

applied_force = 1.e7
md.add_initialized_data('Fx', [applied_force, 0]);

mim_bound1 = gf.MeshIm('levelset', mls, 'boundary(a)',
                       gf.Integ('IM_STRUCTURED_COMPOSITE(IM_TRIANGLE(6),3)'))
md.add_source_term_generic_assembly_brick\
(mim_bound1, 'Fx.Test_u')

I tried to use the 'Normal' keyword within the string, but since the integration takes part within the element and the normal seems to be defined on surfaces only, my python script failed.

Is there a way to apply Neumann Boundary conditions orthogonal to the surface of the discontinuity?

Kind regards,

Patrick