Hi all. I want to make a parametrisation study of a channel length (L). I am defining length as L=Constant(value) where value is a number at the beginning of my code. Then, when I need to define the boundaries I have `outflow = ‘near(x[0], L)’. This gives me the following error: ----------------…

Sorry dokken, I didn’t think it was necessary for this question. Please find an example below: import dolfin from fenics import * from mshr import * import numpy as np import matplotlib.pyplot as plt from matplotlib.ticker import FormatStrFormatter import matplotlib from matplotlib import rc # use …

Consider using the following: class Outflow(SubDomain): def inside(self, x, on_bounary): return np.isclose(x[0], float(L)) outflow = Outflow()

That is great, thank you very much! I used near instead of np.isclose just consistency with my other commands. I am new to Fenics, so could you please break-up for me the components of this class? In particular, the use of the keyword SudDomain and the command(?) on_boundary.

See for instance page 89 of the FEniCS tutorial

Thank you. Don’t I need to explicitly say return on_boundary too?

In this case you do not need it, as there are no other possible dofs close to this point and are not on the boundary. In general you should add an and on_boundary

Set domain length as a variable

dokken December 14, 2020, 2:19pm 2

Please supply a minimal working code example,following the guidelines of: Read before posting: How do I get my question answered?

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Set domain length as a variable

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