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This wiki contains simple tutorial models designed to get you acquainted step by step with the concepts and the syntax of ONELAB models.

The list below gives the main new concepts introduced by each tutorial. Explanations are given as comments directly in the models files, which you can browse directly from the list. Useful tips for using the graphical user interface are also available.

You can download all the tutorials on your computer with the command:

git clone https://gitlab.onelab.info/doc/tutorials.git

Additional examples highlighting various physical models and numerical techniques are available here.

ONELAB tutorial for Gmsh and GetDP

The following examples introduce new features gradually, starting with the Electrostatic microstrip line model. Make sure to read the model files: each new feature is explained directly where it is used in the form of inline comments. See also the ONELAB syntax guide for Gmsh and GetDP and the tutorial on managing variables in Onelab models

1. Electrostatic microstrip line

• Physical regions and Abstract regions
• Stiffness term of a Laplacian problem
• Browse model files

2. Magnetostatic electromagnet

• Right-hand-side term of a Poisson problem
• ONELAB variables
• Boundary conditions at infinity
• Browse model files

3. Linear elasticity - wrench2D

• \nabla u GetDP specific formulation for linear elasticity
• First and second order elements
• Triangular and quadrangular elements
• Browse model files

4. Electrostatic microstrip with floating potentials

• Global quantities and their special shape functions
• Computation of the energy dual, i.e. of the armature charge of the electrode
• More on ONELAB parameters (flags, model options, check boxes, menus, ...)
• Browse model files

5. Thermal contact resistance and floating temperature

• Contact thermal resistance (idealised thin region with hign thermal conductivity)
• Thermal electrode (floating temperature in a region of high thermal conductivity)
• Computation of heat flux through surfaces
• Import of a source field from a file
• Browse model files

6. 2D potential flow with computation of the lift force

• Potential flow, irrotational flow
• Multivalued scalar field
• Lift and Magnus effect, stagnation points
• Run-time variables
• Elementary algorithms in the Resolution section
• Non-linear iteration to achieve Kutta's condition
• Browse model files

7. 2D magnetodynamics - electromagnet and transformer

• Eddy current problems in frequency- and time-domain
• Complex-valued solutions (phasors)
• Use of a template library containing generic formulations
• Browse model files

8. Coupled finite element and circuit equations

• Coupling of finite elements and electric circuits
• Definition of lumped circuit elements
• Creation of netlists combining lumped elements and global finite element quantities
• Browse model files

9. 3D Magnetostatics and magnetic rigid-body forces

• 3D Magnetostatics
• Dual vector and scalar magnetic potentials formulations
• Boundary condition at infinity with infinite elements
• Maxwell stress tensor and rigid-body magnetic forces
• Browse model files

ONELAB tutorial for Python

(See also the onelab.py Python module.)

1. Double pendulum in Python

• Python ONELAB client
• Browse model files

ONELAB tutorial for C++

1. Double pendulum in C++

• C++ ONELAB client
• Browse model files