I sure appreciate a technical rant on the topic :-) Haven't thought about conservation of energy in this context.
I wonder how this concept came to take hold? If it has no explanatory power, why even offer it?
I wonder how this concept came to take hold? If it has no explanatory power, why even offer it?
Other Prandtl papers analyze short, non-infinite wings. But they avoid all the insoluable equations by having the wing fly at infinite velocity! This way, no air moves downwards on average. Prandtl forgets that if the tip-vortices don't move downwards, then also the vortex-shedding goes to zero, and the tip-vortices vanish! By flying at infinite velocity, then pretending that tip-vortices are still created, Prandtl is "searching for car-keys under bright streetlights, where the job is easier" when the actual explanation of lifting force is still hidden elsewhere, out in the darkness.
Heh, another of Prandtl's papers rigorously described the equal-transit-time theory, giving us diagrams, and including it as the explanation for lifting-force. Yet nobody could contradict the Great Prandtl, since his papers were huge walls of interlocking equations, which were all correct. Only his initial assumptions were wrong, and it took about seven decades before physics teachers started seeing the problem.