AeroPython: Classical Aerodynamics with Python
github.com
github.com
Other solutions I am aware of have steep learning curves, so maybe give it a try.
XFLR 5. A nice graphical UI using XFOIL for 2D section CFD and basic algorithms for 3D flow analysis too.
But if you want better fidelity the best open-source CFD suite I'm familiar with is OpenFOAM. Unfortunately you have to have an adequate understanding of the math/physics to use that as OpenFOAM doesn't hold your hand even a little bit. There's really not much of a market at all for "casual flow modeling".
[2] http://python-history.blogspot.com/2010/06/import-antigravit...