I lecture fluid mechanics. There are actually two Bernoulli equations. Remember that Bernoulli’s work is derived for and is only valid along a streamline. A st

I lecture fluid mechanics. There are actually two Bernoulli equations. Remember that Bernoulli’s work is derived for and is only valid along a streamline. A streamline is an imaginary curve that is tangent to the flow field. It’s not some invisible tube, it’s a mathematical representation of a vector field. The first one is the well known one mentioned in the article. It relates pressure and velocity tangent to a streamline. So if the velocity is somehow increased the pressure drops. The second equation deals with pressure changes due to curvature, i.e. force normal to a curving streamline. On an airfoil there is an effective reduction in the area through which the air passes between the surface of the airfoil and a far field streamline unaffected by the airfoil. This increases the velocity (via the continuity equation) which in turn reduces the pressure. The curvature of the airfoil also curves the streamline close to the surface resulting in an additional pressure reduction normal to the surface. You can imagine how this affects a highly cambered airfoil. If anyone is interested here are my lecture notes on the derivation. https://nbviewer.jupyter.org/github/nolankucd/MEEN20010/blob/master/3.2%20Derivation%20of%20Bernoulli%27s%20Equation.ipynb https://nbviewer.jupyter.org/github/nolankucd/MEEN20010/blob...