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Old 16th Nov 2016, 11:26
  #15 (permalink)  
oggers
 
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According to NASA:

neither Newton nor Bernoulli ever attempted to explain the aerodynamic lift of an object...

Bernoulli's equation relates the pressure in a gas to the local velocity. Adding up (integrating) the pressure variation times the area around the entire body determines the aerodynamic force on the body. Now adding up the velocity variation around the object instead of the pressure variation also determines the aerodynamic force. The integrated velocity variation around the object produces a net turning of the gas flow. From Newton's third law of motion, a turning action of the flow will result in a re-action (aerodynamic force) on the object. So both "Bernoulli" and "Newton" are correct...

Arguments arise because people mis-apply Bernoulli and Newton's equations and because they over-simplify the description of the problem of aerodynamic lift...

The most popular incorrect theory of lift arises from a mis-application of Bernoulli's equation. The theory is known as the "equal transit time" or "longer path" theory. In reality, the velocity on the upper surface of a lifting wing is much higher than the velocity which produces an equal transit time...

There is also an incorrect theory which uses Newton's third law applied to the bottom surface of a wing. It neglects the physical reality that both the lower and upper surface of a wing contribute to the turning of a flow of gas...

The real details of how an object generates lift are very complex and do not lend themselves to simplification.
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