The OpenFOAM (Open Field Operation and Manipulation) CFD Toolbox 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 a wealth 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. It is supplied with numerous pre-
configured solvers, utilities and libraries and so can be used like any typical
simulation package. Its structure and hierarchical design are open, so that its
solvers, utilities and libraries are fully extensible.

OpenFOAM uses finite volume numerics to solve systems of partial differential
equations ascribed on any 3D unstructured mesh of polyhedral cells. The fluid
flow solvers are developed within a robust, implicit, pressure-velocity,
iterative solution framework, although alternative techniques are applied to
other continuum mechanics solvers. Domain decomposition parallelism is funda-
mental to the design of OpenFOAM and integrated at a low level so that solvers
can generally be developed without the need for any parallel-specific coding.

WWW: http://www.opencfd.co.uk/openfoam/index.html