OpenFOAM (for "Open-source Field Operation And Manipulation") is a C++ toolbox for the development of customized numerical solvers, and pre-/post-processing utilities for the solution of continuum mechanics problems, most prominently including computational fluid dynamics (CFD).
The OpenFOAM software is used in research organisations, academic institutes and across many types of industries, for example, automotive, manufacturing, process engineering and environmental engineering.
OpenFOAM is open-source software which is freely available and licensed under the GNU General Public License Version 3, with the following variants:
OpenFOAM, released by OpenCFD Ltd. (with the name trademarked since 2007) first released as open-source in 2004. (Note: since 2012, OpenCFD Ltd is wholly-owned subsidiary of ESI Group)
FOAM-Extend, released by Wikki Ltd. (since 2009)
OpenFOAM, released by OpenFOAM Foundation. (since 2011)