Eli5 what bernoulli’s principles is and how it works for aviation. Been watching videos about it and still cant wrap my head around it, thanks heaps for any help.
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Wow. Lots of crazy stuff in here. Let me give a shot at ELI5.
First, “pressure” is made of “dynamic” pressure and “static” pressure. Total pressure remains the same. If you can *increase* dynamic pressure, static pressure will *decrease* to compensate, and vice versa. When standing still, dynamic pressure (created by moving) is zero. If you can increase it, you can decrease static pressure. And key here is, *if you can increase dynamic pressure more on the top of a wing than on the bottom, the static pressure on the bottom will be higher, creating lift*.
How to do that is to make air traveling over the top of the wing go faster than air going over the bottom of the wing – faster air has more dynamic pressure, and so less static pressure. If you compare two molecules of air right next to each other, one going over the top of the wing, and one going over the bottom of the wing, they will start and reach the end at the same time. To make one go faster, you need to travel a greater distance. So the shape of the wing makes the molecule of air going over the top of the wing travel a greater distance to get to the backside of the wing then the molecule of air going under the wing. In order to travel past the wing and end up at the backside at the same time, the top molecule has to go a farther distance, and will have had to have traveled faster. This gives it more dynamic pressure, creating lower static pressure on the top of the wing versus the bottom of the wing, creating lift.
If you want a simple example of Bernoulli‘s principle, in action, which also somewhat debunks this “deflection theory“, take a napkin, or a tissue, hold it tot right under your mouth and blow. The faster air going over the top of the napkin will create a lower pressure area and cause the napkin to be lifted by the higher static pressure beneath it.
Enjoy!
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