This workbench aims to help users set up and run CFD analyses. 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.

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

• Conjugate heat transfer.

Any system on which FreeCAD and the prerequisites listed below can be installed. The following have been tested:

• Ubuntu 16.04
• Fedora 24

• Windows 7 (tested)
• Windows 8 (not yet tested)
• Windows 10 (tested)

Not tested, but a POSIX system. Possible to install and run OpenFOAM.

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

• Latest development version of FreeCAD (0.17 prerelease; requires git commit 12539 or later)
• OpenFOAM (version 4.x tested; other versions may work. However cfMesh currently does not support version 5.x)
• Paraview
• GMSH (version 2.13 or later)
• cfMesh (version 1.1.2)

The latest FreeCAD build of the 0.17 prerelease code can be obtained from https://github.com/FreeCAD/FreeCAD/releases and the latest CFD workbench can be installed into it using the Addon manager:

• After extracting the FreeCAD 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 2016-2), 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.

Set the OpenFOAM install directory in the preferences panel to <blueCFD install directory>\OpenFOAM-4.x (It will be automatically detected in the default install location.)

Likewise, cfMesh can be installed from the Preferences panel. cfMesh is 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 development version of FreeCAD can be obtained from the Ubuntu daily build packages. Alternatively, it 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".

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

Set the OpenFOAM install directory in the preferences panel - typical install locations are /home/user/OpenFOAM/OpenFOAM-4.x or /opt/openfoam4 (It will be automatically detected in common default install locations.)

cfMesh 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 thread.

For previous discussions see CFD WB forum thread.

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)

Oliver Oxtoby (CSIR, 2016-2017) ooxtoby@csir.co.za
Johan Heyns (CSIR, 2016-2017) jheyns@csir.co.za
Alfred Bogaers (CSIR, 2016-2017) abogaers@csir.co.za

We would like to thank Eskom for their financial contribution as well as the following people for their contribution to the code:

Qingfeng Xia (2015) - Original framework; Klaus Sembritzki (2017) - Multiphase