Bernoulli's Principle: Lift, Pressure, and Speed
Bernoulli's principle states that within an airflow of constant energy, when the air flows through a region of lower pressure it speeds up and vice versa. Thus, there is a direct mathematical relationship between the pressure and the speed, so if one knows the speed at all points within the airflow one can calculate the pressure, and vice versa. For any airfoil generating lift, there must be a pressure imbalance, i.e. lower average air pressure on the top than on the bottom. Bernoulli's principle states that this pressure difference must be accompanied by a speed difference.
Bernoulli's principle does not explain why the air flows faster over the top of the wing; to explain that requires some other physical reasoning. It is in providing that additional reasoning where some explanations oversimplify things.
Read more about this topic: Lift (force), Description of Lift On An Airfoil
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