I love OpenFOAM! Its open source, well documented, and can do most practical problems. I have personally used it to study hypersonic flow problems, and low Reynolds number incompressible flows. I have friends that have used it for lagrangian particle tracking, muli-species flow and flows with chemical reactions. Post-processing is very easy because writing post-processing utilities in the OpenFOAM environment is a breeze!
In this section I’ll try simulating different problems for fun, and for research. And discuss complications and issues that I encountered.