The familiar story that the two airstreams splitting at the leading edge must meet again at the trailing edge is simply wrong — the upper stream actually gets there first. A wing lifts because it deflects air downward and because the faster flow over the top leaves the pressure there lower than underneath, and that lift grows with the angle of attack until the flow separates and the wing stalls. The same family of laws governs the three other scenes: density relative to water decides whether an object floats or sinks, the tighter a Venturi throat the faster the flow and the lower the pressure, and once velocity passes a threshold laminar flow breaks up into turbulence.
The familiar story that the two airstreams splitting at the leading edge must meet again at the trailing edge is simply wrong — the upper stream actually gets there first. A wing lifts because it deflects air downward and because the faster flow over the top leaves the pressure there lower than underneath, and that lift grows with the angle of attack until the flow separates and the wing stalls. The same family of laws governs the three other scenes: density relative to water decides whether an object floats or sinks, the tighter a Venturi throat the faster the flow and the lower the pressure, and once velocity passes a threshold laminar flow breaks up into turbulence.
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