Air flow on top of a airplane wing

I am fascinated by the basic laws of everyday events
You've heard the expression "you know more than you can tell"?

I am fascinated by the way we figure out the laws intuitively and subconsciously even when we can't verbalize them.

If you'd like a mind blower, consider the concept of "lift" - not on an airplane wing, but on an information manifold.

In the field of information geometry, statistical distributions of everyday events "look like" everyday Cartesian coordinate systems, and support angles and lengths and distances and all the other math we know and love.

So for instance you can have a surface whose base coordinates are mean and variance, thereby parameterizing a family of (Gaussian) probability distributions.

These "information manifolds' are entirely physical, there is a concept of free energy, and also the concept of the work it takes to travel a path on the surface. Therefore, one can think in terms of a "force" that pushes the system from one state into another.

Here is a short high level primer:


In the link they talk about "belief propagation". And you can think about the forces that would be necessary to lift a belief.

This is what our brains do when we think, we force beliefs up and down through "belief trees" (directed graphs) by applying logical "forces" (in the form of hypothetical initial conditions).
 
I understand that air on top of a wing travels faster than the air on the bottom of the wing ??

This is because air on top has a longer distance to travel

Why is that ??

I assume it’s due to geometry of a wing ??

The air traveling on top has a larger upward trajectory??
 
Bernoulli effect is cool

Wolfgang Langewiesche, the man who, quite literally, wrote the book on flying, disagrees with you.

"Trying to understand the piloting of air¬
planes by concentrating on Bernoulli and Prandtl is like trying to
catch on to tennis by studying just exactly how the rubber molecules
behave in a tennis ball when the ball hits the court and just exactly
how the catgut behaves in the racket when the ball strikes: instead

of simply observing that it bounces!"
 
Wolfgang Langewiesche, the man who, quite literally, wrote the book on flying, disagrees with you.

"Trying to understand the piloting of air¬
planes by concentrating on Bernoulli and Prandtl is like trying to
catch on to tennis by studying just exactly how the rubber molecules
behave in a tennis ball when the ball hits the court and just exactly
how the catgut behaves in the racket when the ball strikes: instead

of simply observing that it bounces!"

Sorry, if you're a pilot you better understand turbulence.

"Observing that it exists" is not enough.
 
Sorry, if you're a pilot you better understand turbulence.

"Observing that it exists" is not enough.

In his classic book, "Stick and Rudder", Langewiesche stresses understanding all aspects of flight, including that induced by wind and weather, in terms of air pushing on surfaces.

From the perspective of the pilot, it's the single best theory of flight to explain why and airplane does what it does, even when you don't want it to.
 
You've heard the expression "you know more than you can tell"?

I am fascinated by the way we figure out the laws intuitively and subconsciously even when we can't verbalize them.

If you'd like a mind blower, consider the concept of "lift" - not on an airplane wing, but on an information manifold.

In the field of information geometry, statistical distributions of everyday events "look like" everyday Cartesian coordinate systems, and support angles and lengths and distances and all the other math we know and love.

So for instance you can have a surface whose base coordinates are mean and variance, thereby parameterizing a family of (Gaussian) probability distributions.

These "information manifolds' are entirely physical, there is a concept of free energy, and also the concept of the work it takes to travel a path on the surface. Therefore, one can think in terms of a "force" that pushes the system from one state into another.

Here is a short high level primer:


In the link they talk about "belief propagation". And you can think about the forces that would be necessary to lift a belief.

This is what our brains do when we think, we force beliefs up and down through "belief trees" (directed graphs) by applying logical "forces" (in the form of hypothetical initial conditions).

Manifolds do not look like everyday objects ... does a circle "look like" a straight line? ... hell no ... what the hell are you babbling about? ...or are you suggesting we can ignore the curvature of the Earth when we consider the action of a wing-through-air for the few seconds we need? ...

Well ... yeah ... in fact ... we use a spherical co-ordinate system for air traffic management ... each airplane is located using latitude, longitude and elevation ... now, here's the clever little bit ... gravity is constant above and below our airplane, so our first derivative is a 2nd dimensional equation instead of the 3rd as you'd have in your Cartesian system ... thus the simplified form of Navier/Stokes ... [giggle] ... manifolds need not apply ...

For this question in the OP ... we need only ask for faith and belief in the Pressure Force ... the egg-heads say this is caused by gravity's effect on fluids ... and it is a REAL force, honest to God, not this bullshit pseudo-force crap ... but real true exchange-of-energy type of force ... we can count the joules ...

Because the bottom of the wing is a shorter distance than above, the air flow must be faster above in order to meet up again at the trailing edge ... we can use Bernoulli's Law to say the faster air above is flowing at lower pressure than below ... such that a pressure force develops under the wing pointed straight up ... thus "lift" as the book Stick and Rudder describes ...

But, alas ... as with anything that involves gravity ... the true explanation lies with the pressure field that surrounds our airplane ... and that's over my paygrade to explain ...
 
Because the bottom of the wing is a shorter distance than above, the air flow must be faster above in order to meet up again at the trailing edge ... we can use Bernoulli's Law to say the faster air above is flowing at lower pressure than below ... such that a pressure force develops under the wing pointed straight up ... thus "lift" as the book Stick and Rudder describes ...
Nuh-uh.

There is no physical law that says the air has to "meet up again at the trailing edge". Where do you get such nonsense from?
 
Nuh-uh.

There is no physical law that says the air has to "meet up again at the trailing edge". Where do you get such nonsense from?

Have you ever heard of a dust explosion? It isn’t the explosion that is so bad. Most often buildings can withstand that. The problem comes when the explosion is done. The air rushing back in. This is the implosion.



Gravity affects everything equally. Gravity is pulling the air down. If something moves the air, like a wing, the air rushes back into the void to refill it. This created the lie that Nature abhors a Vacuum. Most of the Universe is Vacuum. So that isn’t true.
 
Have you ever heard of a dust explosion? It isn’t the explosion that is so bad. Most often buildings can withstand that. The problem comes when the explosion is done. The air rushing back in. This is the implosion.



Gravity affects everything equally. Gravity is pulling the air down. If something moves the air, like a wing, the air rushes back into the void to refill it. This created the lie that Nature abhors a Vacuum. Most of the Universe is Vacuum. So that isn’t true.

Your theory is that the airfoil creates a vacuum?
 
Your theory is that the airfoil creates a vacuum?
Actually, it does create an area of lower pressure. That is what causes the “lift” of the wing. The lift is why we say it is flying.

My point in the Dust Explosion was that after the thermal effect has finished the resulting lower pressure, or vacuum effect, is rapidly corrected by the air rushing back in to fill the void.
 
Actually, it does create an area of lower pressure. That is what causes the “lift” of the wing. The lift is why we say it is flying.

If you take any plane surface, and pass air over it, it will lift in the direction of the incline. It does that because air is pushing one side harder than the other. No vacuum is required.

In fact, any significant vacuum on top of a wing that isn't uniform would significantly disrupt laminar airflow (turbulent flow) and decrease lift.
 
Actually, it does create an area of lower pressure. That is what causes the “lift” of the wing. The lift is why we say it is flying.

My point in the Dust Explosion was that after the thermal effect has finished the resulting lower pressure, or vacuum effect, is rapidly corrected by the air rushing back in to fill the void.

High pressure below the wing, low pressure above the wing ... thus we have a force acting on the wing pointed straight up ... physics says so ...

Not sure about your "grain dust explosion" ... Here's a video {0'30"} ... while the cloud is orange, we're still seeing combustion and the expansion of the cloud ... once this ends, I'm not seeing any return, no implosion ... the individual molecules don't gain enough momentum to create anything but a very minimal low pressure in the middle ... the products of combustion infill this area ... even dynamite isn't strong enough, and here's about five minutes worth and none of these show any return implosion ...

Thermonuclear devices ... well yeah ... note there's no products of combustion to infill ...
 

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