Values of a given point on the interface of two different domain

[lianzha...@gmail.com]

Dear all,

My problem comes from step-46, which couples two different domains. Now, I want to get the values of a given point on the interface, so I use VectorTools::point_value. However, the point on interface has two sets of dofs, the one of which is corresponding to  stokes_fe (velocity_x, velocity_y, pressure, nothing, nothing) and the other one is corresponding to elasticity_fe(nothing, nothing, nothing, displacement_x, displacement_y). When using VectorTools::point_value, the function seems to choose one set of the values. How can I get (velocity_x, velocity_y, pressure, displacement_x, displacement_y) of a given point on the interface?

Thanks for your help.

Best regards,

Leon

[Wolfgang Bangerth]

Is it a point whose coordinates you can easily express in terms of the
reference coordinate system of the cell or face? E.g., the midpoint of a face?
In that case, you can use FEFaceValues which you would initialize with the
cell on the side you are interested in.

If it really is an arbitrary point, then maybe shifting it by an epsilon away
from the interface will work. If you choose epsilon small enough, then the
error introduced that way will be negligible.

Best
W.


--
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Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[lianzha...@gmail.com]

Thank you very much^-^. Using an epsilon is a very smart idea.