What is OpenFOAM
OpenFOAM is a C++ based open source platform/toolbox with a range of standard numerical solvers and pre/post processing utilities for continuum mechanics problems including computational fluid dynamics. In simple and relevant terms, OpenFOAM is a powerful free to use platform which can specifically be used for CFD simulations.
OpenFOAM Advantage :
The structure of OpenFOAM requires a rather clear knowledge of the governing equations, aspects related to discretization, the nature and underlying structure of the fluid domain, mesh structure and the solution methodology to solve a problem on hand. Without some of the basics, even case setup becomes next to impossible. Thus, OpenFOAM enables holistic evolution of knowledge base pertaining to computational fluid dynamics aspects, an aspect which makes OpenFOAM different from other solvers.