This tutorial shows how to perform a simple CFD simulation of the flow around an airfoil.
See the following videos to learn how to generate a mesh using gmsh.
https://youtu.be/QAe72cO-slM
https://youtu.be/iYSMVZQGpbw
gmsh can be downloaded from http://gmsh.info/
OpenFOAM can be downloaded from https://openfoam.com/