Understanding Aerodynamics Arguing From The Real Physics Pdf -

This is the only direct cause of aerodynamic force. For a wing to experience an upward force (lift), it must impart a downward change of momentum to the air.

A wing generates lift by performing mechanical work on the surrounding air mass. It forces a massive volume of air downward. The wing exerts a downward force on the air. The air exerts an equal, opposite upward force on the wing. understanding aerodynamics arguing from the real physics pdf

There is no "lift secret." There are only three universal principles that a fluid must obey. Every aerodynamic outcome derives from these. This is the only direct cause of aerodynamic force

Another common error treats the upper surface of a wing as half of a Venturi nozzle. A Venturi tube requires a solid, constricting physical wall opposite the restriction to force fluid acceleration. In open air, the atmosphere does not act as a rigid ceiling. The fluid is free to expand vertically, rendering the strict Venturi analogy invalid. 2. The True Physical Foundations of Lift It forces a massive volume of air downward

Lift per unit span = ρ × V × Γ

In a steady flow, the mass flow rate (density × area × velocity) is constant along a streamtube. If a streamtube narrows, velocity must increase. This is not a theory; it is a mathematical necessity.