Principles similar to aero, hydro dynamics

[seazal]

When you see a heavy airliner on landing approach, you'd be amaze how such heavy object can float in air. Not many know it's the air pressure differences that can cause it. There are still many who thought it was simply because the wings flap like birds.

It's similar to aircraft carrier floating on water. For the ignorant, it's unthinkable such heavy objects can float on water that is very light.

What are other principles similar to this where seemingly light substance such as air or water can support heavy object?

If Bohmian Mechnics were right, and there would be slight changes to conventional Quantum Mechanics, can the vacuum be biased or taken advantage of such that one can use it akin to airplane using air to fly or aircraft carrier using water to float?

 

[Vanadium 50]

Airplanes have lift because air is directed down. Wings are the agents that do this. Since your argument is based on an incorrect premise, the conclusions are invalid.

 

[seazal]

Airplanes have lift because air is directed down. Wings are the agents that do this. Since your argument is based on an incorrect premise, the conclusions are invalid.

I edited it to "There are still many who thought it was simply because the wings flap like birds.". Many thought birds fly because the wings just flap up and down and they think a boat paddle can cause the boat to fly too given strong flapping, they were not aware of the air pressure thing that creates lift.

 

[Klystron]

I edited it to "There are still many who thought it was simply because the wings flap like birds.". Many thought birds fly because the wings just flap up and down and they think a boat paddle can cause the boat to fly too given strong flapping, they were not aware of the air pressure thing that creates lift.

Can you validate any of these claims? Early Wright flyers had warpable wings but also an engine and prop. I've read early 20th newspaper reports that explain flight better. Any thinking person who has seen or flown on fixed-wing aircraft can see the wings do not 'flap'.

 

[russ_watters]

There are still many who thought it was simply because the wings flap like birds.

I've never heard of anyone who believed that.

When you see a heavy airliner on landing approach, you'd be amaze how such heavy object can float in air. Not many know it's the air pressure differences that can cause it.

It's similar to aircraft carrier floating on water.

For the ignorant, it's unthinkable such heavy objects can float on water that is very light.

While it is due to pressure differences, like a floating aircraft carrier, the cause of the pressure differences is not at all similar to an aircraft carrier.

 

[seazal]

Can you validate any of these claims? Early Wright flyers had warpable wings but also an engine and prop. I've read early 20th newspaper reports that explain flight better. Any thinking person who has seen or flown on fixed-wing aircraft can see the wings do not 'flap'.

Ask anyone randomly in the street why airplane fly. They would only say it's because they have wings. They mostly don't know about the air pressure differences principles that lift the wings.

 

[seazal]

Ask anyone randomly in the street why airplane fly. They would only say it's because they have wings. They mostly don't know about the air pressure differences principles that lift the wings.

I mean most people in the street doesn't know the following. I have actually asked them. They only know it's because they have wings.

So I was asking if there are other principles like this air splitting and lifting that can lift hundreds of tons of steel. It's unthinkable even before the Wright Bothers.

 

[cjl]

Airplanes have lift because air is directed down. Wings are the agents that do this. Since your argument is based on an incorrect premise, the conclusions are invalid.

It is both because wings redirect air downwards (the so-called "Newtonian" explanation) and because they create a pressure difference between the upper and lower surface (the so-called "bernoulli" explanation). Both statements are true, and neither is, in and of itself, sufficient to really understand what is going on with an airfoil, and why the fluid flows the way it does (and therefore why the forces are what they are).

 

[seazal]

It is both because wings redirect air downwards (the so-called "Newtonian" explanation) and because they create a pressure difference between the upper and lower surface (the so-called "bernoulli" explanation). Both statements are true, and neither is, in and of itself, sufficient to really understand what is going on with an airfoil, and why the fluid flows the way it does (and therefore why the forces are what they are).

Yes. It is very clear how airfoiling works. But what year was this first realized or actually first understood? Was it the year 1500s or 1800s?

 

[cjl]

I would say a rudimentary explanation was understood in the 1800s (or perhaps even earlier), but a really good understanding didn't happen until the early 1900s. That having been said, I really don't think anyone believes lift comes from "flapping like birds".

 

[seazal]

I would say a rudimentary explanation was understood in the 1800s (or perhaps even earlier), but a really good understanding didn't happen until the early 1900s. That having been said, I really don't think anyone believes lift comes from "flapping like birds".

But if you will ask people randomly in the street how airplanes fly. They would only tell you it's because they have wings like birds and jet engines. They won't know anything about airfoil principle, at least more than 50% of them don't. I have actually tried asking them. Only scientifically oriented people understood this. But not your average citizen.

That said. The vacuum is only composed of virtual particles and quantum stuff, so we were not supposed to be able to harness it. But casimir plates can take advantage of it. Also due to Lorentz invariance, the vacuum is equivalent at all directions. But if Lorentz invariance was just a local symmetry, an emergence of something more fundamental (this was discussed in the arxiv). If you can influence the more fundamental degree of freedom, can't one bias the vacuum to create something akin to the pressure differences of surfaces in the airfoil principle and building spacecraft s that really on them? The universe is so elegant. It's very unlikely that spaceships were only limited by rockets in deep space and airfoil in atmospheric navigation which are quite medieval in approach.

 

[cjl]

They certainly won't say it's because they flap though. Frequently they'll have some handwavey explanation regarding bernoulli and air over the wing traveling faster, often based on the equal transit time fallacy, but I've never met anyone who thinks that airplanes flap their wings.

Also, I really don't see the relation to quantum mechanics, but I'll admit that I'm an aerodynamicist by training, not a quantum physicist, so my level of understanding of that kind of thing is more at the level of an interested amateur than a true expert.

 

[seazal]

They certainly won't say it's because they flap though. Frequently they'll have some handwavey explanation regarding bernoulli and air over the wing traveling faster, often based on the equal transit time fallacy, but I've never met anyone who thinks that airplanes flap their wings.

Most I asked never heard of Bernoulli or air over the wing traveling faster and stuff. They just know planes have wings like birds. And jet engines were used for take off then the plane glides because of the wings. So it's like they thought the flapping function was replaced by jet engines. Try going to China and ask the natives how planes fly and you would get ideas of their answers. Of course if you ask Silicon Valley engineers, they have better rough idea.

Also, I really don't see the relation to quantum mechanics, but I'll admit that I'm an aerodynamicist by training, not a quantum physicist, so my level of understanding of that kind of thing is more at the level of an interested amateur than a true expert.

 

[jim mcnamara]

@seazal
Several members have asked for scientific citations. Please provide them - from accepted journals or standard textbooks. That is how PF "flies" - we do not correct or condone personal theory. Not citations and the thread will be closed. Thank you for understanding our position.

 

[seazal]

@seazal
Several members have asked for scientific citations. Please provide them - from accepted journals or standard textbooks. That is how PF "flies" - we do not correct or condone personal theory. Not citations and the thread will be closed. Thank you for understanding our position.

What? I was just asking what other principles similar to the simplicity of airfoil. Before the 1800s, it was hard to imagine that mere air flow (that we hardly feel) over curved surface can lift thousands of tons of aircrafts (like space shuttle gliding down). So I'd like to know what other principles of physics have similar nature. I can think of one, hydraulics, what else?

 

[jim mcnamara]

Thread closed.