This workbench aims to help users set up and run CFD analyses within the FreeCAD modeller. It guides the user in selecting the relevant physics, specifying the material properties, generating a mesh, assigning boundary conditions and setting the solver settings before running the simulation. Where possible, best practices are included to improve the stability of the solvers.

The workbench serves as a front-end to the popular OpenFOAM® CFD toolkit (www.openfoam.org, www.openfoam.com).

Disclaimer: This offering is not approved or endorsed by OpenCFD Limited, producer and distributor of the OpenFOAM software via www.openfoam.com, and owner of the OPENFOAM® and OpenCFD® trade marks

As the workbench is still in its early development phase and evolving rapidly, new developments may sometimes change the saved object format. This may mean that some objects do not load correctly from previously saved files, and must be re-generated. For better forward-compatibilty, it is advised that you save the Python script used to generate an analysis (right-click in Python console and choose 'Save history as').

• Incompressible, laminar flow (simpleFoam, pimpleFoam)
• Basic multiphase capability (interFoam, multiphaseInterFoam)
• High-speed compressible flow (HiSA)
• Basic material data base
• Flow initialisation with a potential solver
• Tetrahedral meshing using GMSH
• Cut-cell Cartesian meshing with boundary layers (cfMesh)
• Cut-cell Cartesian meshing with porous media (snappyHexMesh)
• Post processing using paraview
• Porous regions and porous baffles
• Runs on Windows 7-10 and Linux
• Unit testing
• Extension to turbulent flow using RANS (k-w SST).
• New case builder using an extensible template structure
• Macro scripting

• Conjugate heat transfer.

Any system on which FreeCAD and the prerequisites listed below can be installed.

Windows 7-10; 64-bit version is required.

Not widely tested, but possible.

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The CfdOF workbench depends on the following external software, some of which can be automatically installed (see below for instructions).

• Latest release version of FreeCAD (0.17) or latest development version (0.19 prerelease; requires git commit 13528 or later)
• OpenFOAM Foundation version 4.0 or later or ESI version 1706 or later
• Paraview
• FreeCAD plot workbench
• GMSH (version 2.13 or later)
• cfMesh (customised version updated to compile with latest OpenFOAM versions)
• HiSA (High Speed Aerodynamic Solver)

The latest FreeCAD build can be obtained from https://www.freecadweb.org/wiki/Download and the latest CFD workbench can be installed into it using the Addon manager:

• After running the installer or extracting the .7z archive to a directory , run FreeCAD in place (<FreeCAD-directory\bin\FreeCAD.exe).
• Select Tools | Addon manager ...
• Select CfdOF in the list of workbenches, and click "Install/update"
• Restart FreeCAD
• For installation of dependencies, see below.

Note: The CFD workbench can be updated at any time through the Addon manager.

Dependencies can be checked and installed conveniently from the CFD Preferences panel in FreeCAD. In the FreeCAD window, select Edit | Preferences ... and choose "CFD".

The OpenFOAM installation is via the blueCFD-Core package (version 2017-2), with which Paraview comes bundled. This can be installed manually using the above link, or by clicking the relevant button in the Preferences panel described above.

Please note that User Access Control in Windows 10 can restrict write access to the Program Files directory, which interferes with the installation of cfMesh and HiSA in blueCFD-Core. It is therefore recommended that blueCFD-Core be installed outside the Program Files folder.

Set the OpenFOAM install directory in the preferences panel to <blueCFD install directory>\OpenFOAM-5.x (It will be automatically detected in the default install location.)

Likewise, cfMesh and HiSA can be installed from the Preferences panel. They are automatically built from source inside the OpenFOAM environment if installed from the Preferences panel. Note that this is a lengthy process.

Choosing the "Check dependencies" option will verify that all prerequisites have been successfully installed.

The latest release or development version of FreeCAD can be obtained from https://github.com/FreeCAD/FreeCAD/releases (.AppImage files). The Ubuntu PPA daily build packages are an alternative binary option. Otherwise, FreeCAD can be built from the source code at https://github.com/FreeCAD/FreeCAD .

The latest CFD workbench can be installed into FreeCAD using the Addon manager:

• Run FreeCAD
• Select Tools | Addon manager ...
• Select CfdOF in the list of workbenches, and click "Install/update"
• Restart FreeCAD
• For installation of dependencies, see below.

Dependencies can be checked and some of them installed conveniently from the CFD Preferences panel in FreeCAD. In the FreeCAD window, select Edit | Preferences ... and choose "CFD".

However, in Linux, manual installation is required for OpenFOAM, Paraview and GMSH, which should be installed using your distribution's package manager or the links above.

The FreeCAD plot workbench is included in many packages, but in some cases must be installed manually with the command

pip install git+https://github.com/FreeCAD/freecad.plot.git

In future it will be available through the AddOn manager.

Set the OpenFOAM install directory in the preferences panel - typical install locations are /home/user/OpenFOAM/OpenFOAM-5.x or /opt/openfoam5 (It will be automatically detected in common default install locations.)

cfMesh and HiSA can be installed using the Preferences panel described above, and will be downloaded and built from the source code inside your OpenFOAM installation if you have not already done so yourself. Note that this is a lengthy process.

Choosing the "Check dependencies" option will verify that all prerequisites have been successfully installed.

Please discuss issues on the CfdOF dedicated FreeCAD forum. Bugs can be reported on the github project site.

Please first read the guidelines for reporting bugs in order to provide sufficient information.

It is asked that developers should only add functionality or code that is working and can be tested. Dead code, even portions included for possible future functionality, reduces function clarity and increases the maintenance overhead. Our philosophy is 'Do the basics well' and therefore robust operation takes precedence over extended functionality.

Unit testing is currently under development. Where possible, it is asked that all new functionality should be included in the unit test framework.

For consistency please follow PEP8

1. Use 4 spaces per indentation level (spaces are preferred over tabs).

2. Limit all lines to a maximum of 120 characters.

3. Break lines before binary operators.

4. Blank lines

   • Surround top-level function and class definitions with two lines.

   • Definitions inside a class are surrounded by a single line.

5. Imports should usually be on separate lines.

6. Comments

   • Docstrings always use """triple double-quotes"""

   • Block comment starts with a # and a single space and are indented to the same level as that code

   • Use inline comments sparingly. They are on the same line as a statement and should be separated by at least two spaces from the statement.

7. Avoid trailing whitespaces

8. Naming convention

   • ClassNames (Camel)
   • variable_names_without_capitals (Underscore)
   • CONSTANTS_USE_CAPITALS (Uppercase)
   • functions_without_capitals (underscore, preferred as it follows PEP8)
   • functionsWithoutCapitals (Camel instead of underscore is accepted as it is widely used within FreeCAD)
   • __class_attribute (Double leading underscore)

This development was made possible through funding from Eskom Holdings SOC Ltd and the Council for Scientific and Industrial Research (South Africa).

The code is maintained by

• Oliver Oxtoby (CSIR, 2016-2018) oliveroxtoby@gmail.com
• Johan Heyns (CSIR, 2016-2018) jaheyns@gmail.com
• Alfred Bogaers (CSIR, 2016-2018) alfredbogaers@gmail.com

We acknowledge significant contributions from

• Qingfeng Xia (2015) - Original framework
• Michael Hindley (2016) - Initial concept
• Klaus Sembritzki (2017) - Multiphase
• Thomas Schrader (2017-2018) info@schraderundschrader.de - Testing and user assistance