On Oct 3, 4:04 pm, Le Chaud Lapin wrote:

If a person sucks on a straw, the reason the fluid rises has *NOTHING*
to do with Bernoull's principle. It has to do with the balance in
force being eliminated. In particular, the air in the straw is
removed, so the 14.4lbs/square in will lift the fluid in the straw.


So, if it has nothing to do with Bernoulli, what has it to do
with lift? With tables and straws and the like we're talking static,
not dynamic pressures. The airplane uses dynamic AND static
pressures.
In cruise flight (low AOA), I would expect a reduced pressure
on the bottom of the wing, though not as low as on the top. The
velocity of air across the bottom will drop its pressure, there, too.
Air has mass. Anytime you try to push it out of the way,
there will be some reaction. Newton says so. We know this as drag.
But we also know it as lift reaction. A flat plate flying
through the air at some tiny angle of attack doesn't have much faster
air over the top than the bottom, if any difference at all, yet it
will generate plenty of lift. Try this on, if you want to think
outside the box: The airfoil we know is just that: a foil (device to
deceive) to trick the air into flowing over it without breaking up at
much higher angles of attack than a flat plate would let us. So the
leading edge has to have some radius so the air can get around the
corner from the natural stagnation point under the LE at high AOA, and
that curve must gradually taper off toward the rear or the now-
disturbed air would want to separate and turbulate, and if it did that
it would then slow down dramatically, pressure would rise and lift
would decrease. But, happily, Newton is still at work underneath so
the airplane falls, but not as if the wings fell off. We're still
moving forward and the wing is still shoving air out of the way
downward, so lift is still generated.

Dan