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Old 24th April 2003 | 18:40
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Oktas8
 
Joined: Jun 2001
Posts: 889
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From: Australia
Interesting one.

My two cents worth:

Bernoulli - Based on conservation of energy. Quantitatively simple & therefore easy to understand at a basic level. Leads to Lift = 1/2 rho x v squared, which is extremely important later on. Is not particularly accurate - eg cannot handle lift from a flat plate.

Coanda - Based on conservation of momentum. More universally applicable and easier to demonstrate (spoon under running water) than Bernoulli. Unlike Bernoulli, Coanda does explain skin friction & form drag. However, leads to mathematical complexities if the student asks "how much lift is generated?"

What about Newton's laws and Kutta - Joukowski theorem, also known as circulation theory? It's all too mathematical for my poor tired brain...

I use Bernoulli because
a) I can answer the question "how much lift at airspeed X?" and
b) it doesn't need much maths.

But then I also add to my briefs "this is just a simplification - the real world is much more complicated."

regards to all,
O8
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