What is Bernoulli's principle? Use Bernoulli's principle to explain how one of the following works: an airfoil, a curve ball, the wind blowing the roof off a house.

Answer 1

As the pressure goes down the velocity goes up to keep the total energy the same.
1. airfoil, you need to know one more thing, the "Kutta condition" which says that the air flows smoothly off the rear of the wing rather than sneaking around the sharp edge and forming a stagnation point on the upper surface. That means the path is longer around the front and down the top, and therefore the air moves faster over the top of the wing. Low pressure on the top, higher on the bottom ---> force up, fly.
2. curve ball, he spinning ball retrds the flow on one side and speeds it up on the other, pressure is lower on the fast side as you know now so there is a side force.
3. air flow fast over the roof, stops at the walls and windows and doors and inside and underneath. Pressure high under, low over -- Boom!