I am solving a system of PDEs, where one of the unknowns, a vector field q, must satisfy the boundary condition. n is the normal vector to the surface. q⋅n=1 How to apply boundary condition of q?Any help will be thanked.

As i said in the previous post, you need to supply the fiberinnhold PDE to anyone to help you. This is because there are different methods for different PDEs (Lagrange multipliers or Nitsches method). It is also dependent of the shape of the domain, as you can restrict it with Dirichlet conditions i…

Here is my program. The domain is a square with crack inside,I want to simulate hydraulic fracture.The third PDE is about this question. h is a fluid mass flux vector,n is normal vector.dot(h,n)=0.02.I do not know how to apply this kind of boundary.Thank you for your patience. Preliminaries and mes…

First of all, please format your code using ```. Secondly, you should make the code as minimal as possible, as it makes it easier for people to help you, and is more benifical for the community. I would suggest you only add a working code solving the third PDE. You also need to specify which bound…

Sorry about that.I want apply inner(h,n)=1 into crack defined in the program. # Preliminaries and mesh from dolfin import * mesh = Mesh('mesh.xml') # Define Space W = VectorFunctionSpace(mesh, 'CG', 1) h,k = TrialFunction(W),TestFunction(W) # Introduce manually the material parameters #... # Con…

[image] xiaodong_zhang: def Crack(x): return abs(x[1]) <= 1e-3 and abs(x[0]) <= 0.1 As far as I can tell, the crack here is an actual 2D domain (depends on the mesh size), not a 1D domain. As this will be an internal boundary (aligned with the mesh coordinates if your mesh is structured)…

Thanks a lot.I will study the tutorial first and have a try.

After mark the specific internal boundary, I still don’t know how to apply inner(h,n)=1 on the crack,like this:bcbot = DirichletBC(W, Constant((0.0,0.0)), bot)? But I don’t know the specific value of vector h.

As your crack goes along the x-axis, n=(0,1). This means that you can use W.sub(1), and a Constant(0,1) in the bd

What should I do if the crack is a circle? Then the n is not specific.

And I don’t know why I need to define the subdomain.

How to apply boundary condition like this

dokken June 3, 2020, 9:30am 19

Please follow Read before posting: How do I get my question answered?
which describes how to make a minimal working example.

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How to apply boundary condition like this

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