måndag 24 september 2012

Aerodynamics Expertise Without Knowledge

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Under Aerodynamics Questions we read as an answer to the question How Does a Wing Work?:
  • So the reader may be asking which of these theories (Bernoulli, Newton, Circulation) is correct
  • In truth, each is valid in some respect and useful for certain applications, but the ultimate question is which is the most fundamental explanation. 
  • Mathematicians would surely prefer the circulation theory, which is certainly a very elegant approach firmly based on mathematical principles, but it fails to explain what force of nature creates circulation or lift. 
  • Many would argue that the Newtonian explanation is most fundamental since it is "derived" from Newtonian laws of motion. While this is true to some degree, the theory lacks an explanation as to why an airfoil deflects the flow downward in the first place. Even accepting this principle, the idea that an airfoil deflects the flow and therefore experiences lift also fails to capture the fundamental tools of nature (pressure and friction) that create and exert that force on the body.
  • Proponents of this explanation generally deride the Bernoulli theory because it relies on less fundamental concepts, like the Bernoulli and Continuity equations. There is some truth to this complaint, and the theory may be more difficult for the novice to understand as a result.
  • However, both equations are derived from Newtonian physics, and I would argue from more fundamental and more mathematically sound premises than the Newtonian theory. 
  • In the end, I leave it up to the reader to decide.
We see here the collected expertise of aerodynamics being unable to explain anything of value about the generation of lift of a wing, simply giving up and passing the question of How Does a Wing Work  over to the reader. 

But there is a New Theory of Flight giving a true scientific explanation different from the above trivial no-explanations.

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