OpenFOAM® is a toolbox for performing continuum physics simulations, mainly fluid simulations, and is licensed as an open-source software under the GNU GPL (General Public License) v3.
OpenFOAM® is equipped with a rich set of numerical calculation libraries and abundant physical models such as fluids, enabling simulations comparable to commercial software.
Since it is open source, it can be parallelized indefinitely without being limited by the number of licenses (license fee) as in the commercial software.
These features have been accepted and are now used by research institutes and companies around the world.