The_navigator© wrote in message ...
Where do you get these ideas? Of course energy conservation laws
consider (and implicitly include) friction losses, compression and
turbulence.

Now just because you are familiar with *one* form of the Bernouille
equation does not mean that is the only form. It is possible to derive
forms for any set of integral boundary conditions with the proviso that
you follow a streamline for continuity. Finally, although you seem to
have missed it, the Bernoulli equation expressly considers compression
of a fluid. -it comes into the density term(s).

As I said, we understand how a sail works but you seem to be struggling.

Cheers MC

Leonard Eulers so called "Bernoulli equation" is the 1D (one
dimensional case) of his 3D equations for an non existing,
mathematical modeled fluid!

Bernoulli equation is the integralform of Newton second law F=m*a!

It is easier to show the direction of the Lifting Force using Newton´s
second law directly.

Many books explain Lift with the so called "Bernoulli effect", which
means that " high airflow velocity causes low airpressure"!

Professor Dooley shows here below that this is wrong:

According to Professor Dooley, Millerville University, it will take
one generation to understand Bernoulli equation and that " high
velocity does not causes low pressure".

http://muweb.millersv.edu/~jdooley/m...erap/eulap.htm

Professor Dooyley writes down the page:

"One confusing detail about Bernoulli's equation needs discussion: In
elementary treatments it is often stated that, because of Bernoulli's
equation, high velocity causes low pressure. This is like saying that
the high velocity of bullet leaving a gun caused the low pressure of
the gas outside the barrel of the gun. The field treatment embodied in
Euler's and Bernoulli's equations does not discuss cause and effect.
The field view tells us what parameters "go together" without implying
that one causes the other. If we trace back to the roots of these
equations in Newton's laws, we can extract a cause and effect
statement: Forces are said to cause accelerations. In the same sense,
pressure gradients cause changes in velocity; not the other way
around."

In real aerodynamic books one never finds the expression "Bernoulli
Effect"!

Wings of all new airliners are almost flat on upper surface!

That´s called "Supercritical Wings" and they save their operators (as
example airbus340 ) some 15 % over older aircrafts (Boeing 747-400)!

http://aerodyn.org/HighSpeed/supercritical.html

They now have longer airflow path below the wing compared to to upper
surface!

Some Professors explains Lift with "The Circulation Theory"! But
Potential Theory and it´s correction, the superpositioned "Circulation
Field" is not reality, only a mathematical model!


Jan-Olov Newborg