Themes
The exact theory is wrong
Ideal flow is closed-form, elegant and predicts that an aeroplane needs no engines. Every honest account of this subject is organised around what that failure reveals.
One number decides the regime
The same shape in the same fluid behaves completely differently at different Reynolds numbers. The shape is not the question; the ratio is.
Lift is circulation
Not shape, not equal transit times, not air pushed down in the way usually claimed. Lift is the circulation round the body, and the Kutta condition is what fixes it.
Everything happens in a thin layer
Viscosity is negligible almost everywhere and decisive in a film a millimetre thick, and that film decides drag, stall and the wake.
What is conserved
Mass, momentum, circulation, vorticity. Every result worth having is a statement that one of them cannot go anywhere, and every check in this site's solver is a test that it did not.
A smooth picture proves nothing
Streamlines are smooth whatever nonsense produced them. A flow figure is only worth as much as the conservation laws it was checked against.
Taught wrongly, everywhere
Some of the most repeated explanations in physics education are in this subject, and they are false. Stating them fairly and then testing them is more useful than ignoring them.