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Dave Doe writes:
While it's true that the Bernoulli effect is part of Newtonian mechanics - I want to know what the ratio of (gonna have to rephrase this aren't I) is: * an airfoil where the camber on both sides is equal and opposite (mirroed) vs * an airfoil that is shaped to produce lift via Bernoulli effect. An airfoil doesn't need a specific shape to produce lift, as long as it's reasonably flat. The lift is ALWAYS produced by diverting the flow of air, no matter what the camber of the airfoil. And in airfoils, Bernoulli's effect ALWAYS has a hand in diverting the air flow, again no matter what the camber of the airfoil. I'll rephrase it a second time. What percentage of extra lift is gained from: a) a plank of wood (can only produce lift via angle of attack) vs b) a plank of wood that is an airfoil - and is getting lift from both angle of attack and the Bernoulli effect. The distinction you are making doesn't exist. A plank of wood is an airfoil when air flows over it and it has a positive angle of attack. Newton and Bernoulli are always involved. There is no lift without positive angle of attack. No special shape is necessary for the plank, but it should be relatively flat and roughly edgewise to the air flow (apart from the positive angle of attack, which is mandatory). Here are some articles - but they produce no data to show the addidtional lift obtained by the Bernoulli effect. Because no additional lift is obtained. It's impossible to dissociate Bernoulli from Newton for airfoils. The lift always comes from Newton, the diversion of airflow that invokes Newton is due to Bernoulli (and other effects, depending on how one looks at things). And here is a third re-phrase... * A yacht that has a sail made of unbendable stiff material (will not point as high and go as fast as)... * A yacht that has a sail of normal material and has an effective airfoil shape and produces lift perpendicular to the sail (via the Bernoulli effect). A flat sail will produce lift just as well as a curved sail. And I don't want to get stuck on the pedantics of Newtonian physics encompassing the Bernoulli effect ... Perhaps that explains why you haven't thus far understood the explanations you've received. |
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