OpenFOAM is a programming language for writing solution algorithms for complex physics. The large number of solvers cover a wide range of algorithms which are readily accessible. The users can adapt these algorithms for their specific needs or experiment with new ideas.

The full set of standard differential operators (, , , ,,) are implemented in OpenFOAM using the second-order finite volume method on arbitrary shaped cells. For further details see the chapter on discretisation procedures in the the OpenFOAM User Guides.

OpenFOAM provides a comprehensive range of discretisation schemes. These can be selected at run-time for each term in the equations being solved, allowing full control over accuracy, boundedness and conservation. Examples of well-known equation coupling algorithms, e.g. PISO and SIMPLE, are implemented in top-level codes - the simplicity of the code syntax means that the codes provide the best description of the algorithm itself.