Questions tagged [fenics]
Questions about the finite element method software FEniCS and its subpackages (Dolfin, UFL, FFC).
102
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How to constraint the tangential gradient on a boundary in FEniCS?
The problem I'm considering is a 2D scalar PDE.
The domain $\Omega$ is a disk with two holes $\partial\Omega_1$ and $\partial\Omega_2$ and an external boundary $\partial\Omega_0$.
The PDE and boundary ...
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1
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113
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How to generate mesh for space-time FEM method in FEniCS?
suppose that I have a region called $\Omega $,suppose that this is a 2D or 3D region, how to generate the corresponding space-time mesh by using FEniCS? and how to extract the boundary and implement ...
- 193
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eigenvalues of inhomogeneous Helmholtz equation violate superposition using FEM
I am trying to solve the in-homogeneous Helmholtz equation with damping and forcing using finite element method (FEM) with FEniCSx. The equation is;
$c^2\nabla^2p - c^2\omega i d \nabla^2p + \omega^2 ...
- 11
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Neumann BC in the current configuration in a finite-strain problem
For a hyperelastic problem, I understand the variational formulation can be written as the minimisation of $\Pi$ with
$\Pi = \int_{\Omega} \psi( \pmb{u} )dx - \int_{\partial\Omega} \pmb{T}\cdot \pmb{u}...
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Accessing nodal and degree of freedom organisation in the solution vector in Fenics and Firedrake
Context
Let suppose a solution to a finite element problem (associated to a mesh) stored in a vector $X$ of size $(N \cdot d)$ corresponding to $N$ nodes in the mesh and $d$ degrees of freedom for ...
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1
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88
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How can I define an equipotential surface/volume in FEniCS?
I want to solve electrostatic problem for potential. Charge density and medium permittivity are known, so is the potential of a grounded surface. I know how I can implement that.
But I would like to ...
- 123
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99
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Solving for two interconducting fluids in FEniCS
I'm trying to model in FEniCS a steady-state situation in which a coolant fluid flows through a nuclear fluid. There is finite rate of conduction between the two fluids. The simulation should output ...
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Weak Formulation of Poisson's Equation for Electrostatics with Surface Charge
I am currently attempting to use FEnICS to solve an electrostatic problem with two materials of different permittivity $\varepsilon_1$ and $\varepsilon_2$ forming an interface:
Consider a domain $\...
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236
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Solving coupled PDEs with self-consistency condition
I am figuring out how to attack a problem (the Usadel equations of superconductivity) in which I need to solve a set of nonlinear PDEs for the fields $\{G_i (r)\}$
$$ U(G_i(r), \nabla G_i(r), \Delta(r)...
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111
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Dolfin convert : How to interpolate data at vertices of (3D) cells?
I hope that one of you guys can help me because i have been stuck here for a week.
I am trying to read a gmsh file (.msh) using dolfin convert to XML and then download it with dolfin.
The thing is ...
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214
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How to use FEniCS to calculate the electric field of an isolated charged sphere
Initially I thought that this is the kind of question which ought to have already been answered in the form of an example online, but so far I haven't found one. I will admit that I am very new to ...
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FEM with elastic inhomogeneous properties leads to mesh-induced anisotropy
I'm solving an elastic homogenization problem and I'm having problems with mesh artifacts.
I would like to first give a brief summary of what I do: I have a system with inhomogeneous (but isotropic) ...
- 131
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Add orthogonality constraint to PDE over entire domain finite element
I have a nonlinear differential equation for $u:\mathbb{R}^2\rightarrow\mathbb{R}^3$ that I can express in the form:
$ \nabla (g(u)_{ij} \nabla(u)^j) = 0 $
which is similar to the "Nonlinear Poisson" ...
- 121
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609
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Time-dependent Schrodinger equation implementation in FEniCS
For our Bachelors thesis we're trying to solve the Schrodinger equation $i\partial_tu = -\nabla^2u+Vu$ in FEniCS. Given the domain $[-5, 5]^2$ with an initial value of $u_0(x, y)=e^{(-2(x^2+y^2))}$ ...
- 119
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Heat diffusion simulation in a 3D piston using FENICS
I'm trying to simulate the heat diffusion in a 3D piston. I marked the boundaries on GMSH.
I have used a Dirichlet BC of 300 on the top face of piston. But the results look abnormal. There is a ...
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