John Mallinckrodt is getting me closer to the explanation, I believe.
What I need now is a statement of Bernoulli's principle. I can't seem
to find it codified anywhere, and I have been assuming that it is the
popular one I have seen quoted which states that the pressure on a
surface which has an airstream moving past it is reduced from the
hydrostatic pressure in the airstream by an amount which increases
monotonically with relative velocity. Perhaps I am being a bull in a
china shop here. I don't know what Bernoulli's principle is because I
never invoke it to explain anything; I have never been particularly
satisfied by explanations based on it, and I have others which are
more satisfying to me. If some of the students who ask me are not at
the level appropriate to my explanation then I let curve balls and
other related phenomena remain mysterious to them, like the standard
model of elementary particles is to me. I know that others may teach
*both* these topics to their students, but I have lots more things I
can actually get students to understand.
OK, so John has convinced me that my understanding of Bernoulli's
principle is defective. I accept that, and now I want one of the
Bernoulli defenders to give me a statement of the principle I can
understand, a real teaching challenge, I'd say.
Incidentally, the Bernoulli's equation I do know about assumes
inviscid and incompressible laminar flow. Bernoulli (one or another
member of the family) had nothing to say about the problem of curve
balls in that equation (or theorem). As my calculation showed, this
is really a problem in turbulent fluid flow.