My choice of software for CFD support
As explained here, my job involves studying the physics of flows by numerically solving the equations governing fluid behaviour. To do this, a number of tools are essential:
- CAD (Computer Aided Design) software, to build the geometry and mesh.
- CFD (Computational Fluid Dynamics) software, to solve the problem numerically.
- 3D visualisation software, for analysing the results.
With regard to each of these categories, multiple solutions exist. However, they can be separated into two main groups: commercial software, and Open Source software. With NEMOSFLOW, I have chosen to specialise mainly in the use of Open Source software to process my studies. I’m using this article to justify this choice, and to give you a brief description of the software I’m currently using the most.
The open source choice
By definition, Open Source software is software with source code that anyone can inspect, use, modify and improve. This brings many advantages, of which I have become a particular fan.
Transparency
Access to the source code allows you to know every single line of programming, and to understand exactly how the software in question works. In the world of CFD, this can be particularly useful for optimising a simulation, when you want to assess its physical relevance or analyse problematic results, for example.
Optimisation and flexibility
Open Source software is often natively designed to be easily modified by users (by adding extra modules, etc.). So, starting with the original source code, it is possible to add to it to meet your own needs. In CFD, for example, this could mean adding a new model or a new physical law, which will enable the process you want to model to be handled correctly.
Safety and stability
Well-known Open Source software has a very large number of users, including many experts. The transparency of the source code and the large amount of feedback from users ensure that the software in question is of the highest quality on an ongoing basis. It also guarantees its longevity: Open Source software cannot disappear overnight as a result of a change in company policy.
Cost containment
Obviously, and in all honesty, free access to Open Source software represents an undeniable advantage for freelance activity, thanks to the absence of the significant costs that can be present in the case of a commercial licence.
Community aspect
Finally, the Open Source world is based on sharing, exchanging and passing on knowledge. Every user can contribute to the edifice, and work for the common good. These are values that I hold dear, and that I strive to pass on through my work.
Main used software
Although this list is not necessarily exhaustive, it does represent the bulk of my current tools. The description I have given is very concise, so don’t hesitate to have a look at the sites mentioned.
OpenFOAM
OpenFoam is a multi-physics platform developed by OpenCFD Ltd, itself owned by ESI Group. Based on the finite volume method and mainly developed in C++, it consists of many solvers, each dedicated to a given type of flow. One of its strengths lies in the ease of implementing new models, thanks to the very intuitive syntax used in its C++ libraries.
This code is highly parallelizable. It is also provided with pre-processing (mesh, etc.) and post-processing (paraview) tools.
For more information : https://www.openfoam.com/
Code Saturne
Code_Saturne is a fluid mechanics solver developed by EDF R&D. It is based on a finite volume type approach, and accepts most meshes encountered today (structured or not, compliant or not, elements of any type: tetrahedra, hexahedra, pyramids, polyhedra, etc.). This solver is designed for incompressible or weakly compressible fluids, with or without turbulence, with or without heat transfer. In addition, many modules have been developed, making it possible to deal with particular physics (atmospheric flows, combustion, turbomachines, MHD, multiphase flows, etc.).
Finally, this code is highly parallelizable and can be coupled with other software.
For more information : https://www.code-saturne.org/cms/web/
Syrthes
Syrthes is a software based on the finite element method, allowing to process heat transfers between solids: conduction and radiation in a transparent medium. It also incorporates evaporation and condensation models. Highly parallelizable, one of its great strengths lies in the possibility of being coupled with Code_Saturne, to study combined heat transfers and thus add convective exchanges to the whole.
For more information : https://www.edf.fr/groupe-edf/inventer-l-avenir-de-l-energie/r-d-un-savoir-faire-mondial/nos-offres/codes-de-calcul/syrthes
Salome
Salome is a simulation platform developed by EDF, the CEA and other partners. It allows in particular to build geometries and meshes, and also contains post-processing tools. One of its strengths lies in the possibility of using python scripts, which automates the generation of cases and makes any type of parameterization easy.
For more information : https://www.salome-platform.org/?lang=fr
Gmsh
Gmsh is a software based on finite elements which allows to create, among other things, geometries and meshes. One of its strengths lies in the possibility of using scripts (syntax close to C), which automates the generation of cases and makes any type of parameterization easy.
For more information : https://gmsh.info/
Paraview
Paraview is a data visualization software developed by Kitware, based on the VTK library. It is a very powerful post-processing tool, the principle of which is to apply different filters to the loaded data to arrive at the desired visualization, both in 2 or 3D and in the form of curves or others. It also allows for automation through the use of python scripts.
For more information : https://www.paraview.org/
En conclusion
The choice of Open Source is in line with my values and consistent with what I want to convey through my business. But I would like to make it clear that it is above all a personal choice, far from any judgement towards in-house or commercial software. In all honesty, I regularly have to use them!
If you’d like to discuss this, please don’t hesitate to contact me.