Skip to main content
Share Your Experience: Take the 2024 Developer Survey

Questions tagged [fenics]

Questions about the finite element method software FEniCS and its subpackages (Dolfin, UFL, FFC).

25 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
9 votes
0 answers
435 views

Simple turbulence model appropriate for buoyancy-driven cavity like problem

Which turbulence model is suitable for resolving incompressible buoyancy-driven flow of a fluid within an cylindrical ampoule? I prefer turbulence model which is sufficiently simple so that fully ...
Jan Blechta's user avatar
6 votes
0 answers
703 views

Stochastic Galerkin projection approach for using generalized polynomial chaos expansion (GPCE) in solving PDE

I want to know if there is any way to define the test and trial function in the way that I want instead of using the default functions. So if I want define the polynomial and basis and coefficient, ...
Bahram's user avatar
  • 111
5 votes
0 answers
1k views

Poisson equation with pure Neumann boundary conditions (using FEM)

I am trying to derive the correct variational form for the Poisson equation with pure Neumann boundary conditions, and an additional contraint $\int_{\Omega} u \, {\rm d} x = 0$, as described in this ...
Maarten's user avatar
  • 51
4 votes
0 answers
543 views

Fenics: Result of Steady state dynamic linear elastic doesn't match with actual values

I solved the steady state dynamic linear elastic model in a solid. My equation is a function of frequency and the strong form is: $$\operatorname{div}(\operatorname{stress}(\vec x, w)) + w^2 \rho u( \...
Bahram's user avatar
  • 111
3 votes
0 answers
162 views

Petrov-Galerkin enrichment method for Darcy equation

I was reading about Petrov-Galerkin Enrichment Method for Darcy equations. Here are a couple papers that discuss this in detail: A Petrov–Galerkin enriched method: A mass conservative finite element ...
Justin's user avatar
  • 791
3 votes
0 answers
432 views

A Question About Weak Forms in Fenics

Is it possible to use test and trial functions from two different function spaces (defined over two different meshes) in a single weak form? Under what conditions can I do this (eg., each term in the ...
Aditya Kashi's user avatar
2 votes
0 answers
378 views

Stationary 2D/3D Navier-Stokes source code

Trying to solve stationary Navier-Stokes problem for incompressible laminar Newtonian fluid. I've found a couple solutions for instationary Navier-Stokes equations (like FeniCS examples or CFD Python)...
Igor Kustov's user avatar
1 vote
0 answers
26 views

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 ...
Guillaume Faye-Bédrin's user avatar
1 vote
0 answers
75 views

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 ...
Victor Bigand's user avatar
1 vote
0 answers
228 views

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)...
skdys's user avatar
  • 171
1 vote
0 answers
56 views

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" ...
zephyrus's user avatar
  • 121
1 vote
0 answers
592 views

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 $u_0(x, y)=e^{(-2(x^2+y^2))}$ ...
Anton Scotte's user avatar
1 vote
0 answers
527 views

Immersed boundary method in FEniCS?

I have looked at the FEniCS tutorials and documentation but I cannot find any mention to the possibility of implementing an immersed boundary method (IBM) for fluid dynamics. In particular, I want ...
ares's user avatar
  • 155
1 vote
0 answers
44 views

Setting up diffusion with integral B.C. in Fenics

I'm trying to model diffusion through a cylindrical domain $D = \{ (x,y,z) : x^2 + y^2 \leq 1, \;\; 0 \leq z \leq 1\}$. The is an initial concentration of the diffusant at the upper flat surface, ...
ec92's user avatar
  • 111
1 vote
0 answers
135 views

computational tool for higher order Lagrangian interpolation for finite element

In finite element, I can calculate the Lagrangian interpolation shape functions for each degree of freedom in an element, from the the number of nodal degrees of freedom and the number of nodes ...
user294664's user avatar
1 vote
0 answers
415 views

How to add a Ricker Wavelet (Mexican Hat) to a 2D/ 3D fem mesh?

I have a 2D square mesh and a 3D beam shaped mesh and I want to propagate a seismic wave in them. I am trying to simulate them using Open source FEM codes (fenics). I have left the top surface to be ...
CRG's user avatar
  • 347
1 vote
0 answers
214 views

Weak form for elastoplastic wave propagation

I am trying to simulate elastoplastic seismic wave propagation using Fenics Solid Mechanics Application. The app. provides some quasi-static demos to show elastoplastic behaviour in a cube/ beam/ ...
CRG's user avatar
  • 347
0 votes
0 answers
58 views

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 ...
Ekrem Ekici's user avatar
0 votes
0 answers
108 views

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 ...
nesrine's user avatar
0 votes
0 answers
206 views

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 ...
John Tiessen's user avatar
0 votes
0 answers
429 views

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 ...
Black Heart's user avatar
0 votes
0 answers
155 views

FEniCS, refinement not 'respecting' domain boundary

Short question: how to ensure that extra points are not included as 'boundary' points after calling the refine function. More details. I am working with a hexahedral mesh in $3$d. Let $X$ be the set ...
Tucker's user avatar
  • 189
0 votes
0 answers
185 views

FEniCS implementation of Maxwell equations for a dipole antenna

someone knows where I can find a FEniCS implementation of Maxwell equations for a dipole or other type of antenna? I mean a dipole antenna with an arbitrary geometry of every 'leg' in the dipole.
S. Feunmajer's user avatar
0 votes
0 answers
88 views

Coupling 1D-3D problem in FENICS

I was wondering whether any of you knew if FENICS has the capability to solve coupled 1D-3D problems that are linear non-iteratively? As an example, pipes embedded in a porous domain will provide ...
CapillarySale's user avatar
0 votes
0 answers
96 views

Stokes Equation fails to converge for an ellipse

This might be because of the mesh, but the following code blows up for all values of b not 1. Does anybody have any experience working with the ellipse mesh in Fenics? ...
user242538's user avatar