[email hidden] (Kerry Wilson) wrote in message
news:<[email hidden]>...
Quoted message said:rtk <[email hidden]> wrote in message news:<[email hidden]>...
Quoted message said:I lost the thread, so I have to start again.
I e-mailed Emil Kazez, who is in his office preparing his lecture for physics 445 or some such,
about the following post from J-O Newborg:
There's no such thing as "Bernoulli Lift" in the literature, because Bernoulli didn't
study lift.
Daniel Bernoulli did not even wrote an equation!
Leonard Euler wrote the one dimensional version of his 3D equations in 1754 and called it
"Bernoulli equation"!
Equations does not explain the Physics very well, as they are all parts of mathematical models.
Action/reaction is the physics and Bernoulli explains that physics very bad!
Jan-Olov Newborg
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
E.K. responded:
I don't who wrote the B equation first. Where an air stream speeds up the pressure decreases,
airplane wings are not flat in order to take advantage of this. It is hard to think that B
anticipated or worked to improve air lift, however, it is still reffered to as the B effect.
Even though Newtons laws of motion and his third law (action=reaction) are at the basis of all
classical mechanics, there is no reason to think that he anticipated the B effect/equation.
Ruth Kazez
Daniel Bernoulli did in fact study fluid dynamics and was seminal in putting hydrology on a sound
scientific foundation. He did not study "lift", per se, because the most important fluid dynamics
problems of his day revolved around sailing vessels rather than powered flight.
Leonard Euler was Bernoulli's foremost student. He named the well-known pressure law after his
mentor because it derived directly from Bernoulli's earlier hydrologic studies. So even though
Bernoulli himself did not derive his famous equation, he nevertheless laid the groudwork which led
to its discovery by Euler. Physicists have a long and illustrious tradition of honoring their
predecessors by naming laws which they have discovered after those on whose work theirs is based.
May it ever be so!
Leonard Euler and Daniel Bernoulli were both students of Daniels father Johan Bernoulli.
Daniel went to St Petersburg with his brother. After his brothers death, Leonard was asked to go
Petersburg as company for Daniel.
At age 34 in 1734, Daniel showed his father Johan some manuscript of Physics. From that day on
Johann never talked to Daniel again. They became enemies for the rest of his life!
First Leonard Euler never was a student to Daniel Bernoulli, but both Leonard and Daniel were the
students of Johan Bernoulli, Daniel father!
In 1738 Hydrodynamika he did not wrote any equation at all, because that mathematics was not
available in 1738. It was in 1754 Lagrange and Leonard Euler presented the 1 dimensional equation as
a special case of Eulers 3 D equations for ideal/perfect fluids. Ideal/perfect fluid is a physical
non existing, mathematical constructed/ modelled fluid!
All this history can be read in several books like:
A History of Aerodynamics: And Its Impact on Flying Machines by John D. Jr Anderson (Author), Jr.,
This is a very interesting book. Prof. Anderson writes about "Bernoulli Equation":
"None of the family Bernoulli, father Johann or son Daniel, wrote the
s.k Bernoulli equation, they did not even understand "Pressure property of Point".
It was Euler/Lagrange who set up the equation in 1754, 16 years after Daniels book "Hydrodynamika"!
Jan-Olov Newborg
