The decision to make the software fully open source was taken to service the needs of CFD users in research, development and consultancy who can benefit greatly from perpetual free access to what is essentially a programming toolbox for CFD. The old product was always released with approximately 70% source code and found use at a number of large commercial engineering companies, consultancies and approximately 90 academic institutions in over 30 countries. As a fully open source product, it is expected that OpenFOAM will attract many more new users.

The OpenFOAM (Field Operation and Manipulation) software package can simulate anything from complex fluid flows involving chemical reactions, turbulence and heat transfer, to solid dynamics, electromagnetics and the pricing of financial options.

The core technology of OpenFOAM is a flexible set of efficient C++ modules. These are used to build an archive of: solvers, to simulate specific problems in engineering mechanics; utilities, to perform pre- and post-processing tasks ranging from simple data manipulations to visualisation and mesh processing; libraries, to create toolboxes that are accessible to the solvers/utilities, such as libraries of physical models.

While OpenFOAM can be used as a standard simulation package using the standard solvers, utilities and libraries, it offers much more. Since it is supplied a suite of C++ libraries, mostly with source code, users have total freedom to create or modify a solver, utility or library.