Best talk ever. A well-know Brazilian RUclipsr, called Lito Sousa, from Aviões e Músicas, made a resumed explanation, using the same exampled of yours. This truly shows the potention of accurate, clearly-explained scienctific info, and I'd like to thank you. Your work product is to be commended worldwide.
Babinsky is wrong, there is a constant for Bernoulli in a system open to the atmosphere: it is atmospheric pressure. The flow generated by the hairdryer has kinetic energy, but its total pressure is still atmospheric pressure. Static pressure inside the flow is much lower than atmospheric pressure. This is how carburetors work.
Professor H. Babinsky explains curvature generates pressure difference that is the source of the lift. It is applicable to the sail, the heeled hull, and and the keel. In addition, it is also applicable to the rotor ship with the spinning cylinder. Shape generates function, indeed.
39:05 I don't agree, when you pour a liquid and some of it runs down the side of the container is because of adhesion. If it was the coanda effect, it would increase when pouring faster.
@@synergy6294 It is correct, but a little limited. He doesn't explain just how those pressure changes are caused. The full physics is not too difficult, but so many others don't understand the simple physics of the causes.
The illustration of the sailboat is incorrect as any sailor can tell you. The air does does not flow over the leeward side of the sail the same way as the windward side. If it did, the sail would merely flap as it does when you head directly into the wind. When the sail is full and trimmed, there are eddies of air close to the leading edge (behind the mast) and the wind rushes over the eddies like it does a wing. You can see this on a sail that has "telltales" (short 6-8 inch pieces of wool yarn) attached to the sail a few feet above the boom in a line from the belly (near the mast) to the leach (the trailing edge) of the sail. The one near the mast will be fluttering all over and sometimes be pointing straight up the sail at twelve o'clock. The rest will hang at progressively higher angles from the vertical to horizontal (6 o'clock to 3 o'clock) as they approach the trailing edge, with the one on the edge streaming straight out to 3 o'clock as you would expect. In fact, a good helmsman will steer and trim the sails watching the telltales to get the most speed out of the boat.
He is just showing a simplified 2d flow to make the point that a sail is like a wing on its side. What you have described is the 3d flow around a real sail. It is only to be expected that tell tales just above the boom will be trailing ‘down’ because the local airflow is trying to get under the boom (ie from high pressure to low pressure side). It is exactly the same concept that gives rise to wing tip vortices.
46:00 minutes Very nice demonstration of the common bernoulli explanation. On the left we have a fat low resistance foil, and on the left we have a foil that has much more resistance. So, the greater the differential I'm resistance between top and bottom then the greater the flow speed differential and the greater the pressure differential.
can u explain why then water rises up in a straw when we blow over the straw? the explanation they give is the air above the straw is moving so it have slower pressure but it seems so flawed
The "Rubber Sheet" explanation of Gravity using Gravity = Negative Lift, is a similar pattern of discovery of a specific Form in Function, by "design" = frequency density-intensity alignment of "conducting" resonance-location cofactors in prime superposition, ie "Form follows Function" and e-Pi-i sync-duration connectivity function operates on itself, "module-ates", self-defining Real-time Number substantiation. A consequence of this proof-disproof in Theoretical Design Testing, is that the explanation of Observable Actuality Conception is the reference-framing pure-math relative-timing ratio-rates-> Circuitry of QM-TIME, instantaneous "creation" condensation-quantization = Quantum pure-math-fields oscillation, ..axial-tangential @.dt zero-infinity orthogonality sync-duration, for superposition resonances-> net vector-values temporal superposition apparent "flow", and the cause-effect omnidirectional-dimensional information-pressure, which is Fractal Quantum Operator Logic Fields Modulation Mechanism, ..at the Centre of Time Duration Timing Singularity.., aka Inflation, Gravity, line-of-sight frequency superposition, because frequency aligned-> Cofactor Conduction, radial projection-drawing holographic phenomena such as density-intensity real-numberness condensation modulation matter, and so on. Reciproction-recirculation Singularity synthesises an AM-FM holographic 0-1-2-ness 3D-T pictorial image, by e-Pi-i log-antilog interference.., so => allowing the Rubber Sheet to represent the plasticity of functional-temporal logarithmic hyperfluid vertices in vortices, lifted = floating or levitating, apparently on nothing, actually embedded in Superspin-foam Temporal Totality. Putting things in perspective, 0-1-2-ness line-of-sight Fluxion-Integral superposition =i-reflection on the picture-plane projection-drawing image containment.., makes the balanced orthogonal-normal pure-math relative-timing ratio-rates Equation in the Holographic Principle Imagery, a bit more interesting. Especially if you begin with the Calculus of Logarithmic Time Condensation Communication here-now-forever. Resonance is a very simple concept to grasp Mathematically-Musically, in a fractal AM-FM conic-cyclonic Centre of Time Duration Timing Conception way..
14:22 His debunking of the photocopier paper experiment is itself bunk. When he holds it down, he tensions the paper in such a way that the Bernoulli effect can't work it. It might have just as well been a sheet of cardboard. If you hold a sheet of paper vertical to the earth (from which most gravity comes) and allow it enough flexibility to sway, then the experiment proves Bernoulli. As the forced air stream moves downward, it entrains higher pressure air into the flow on the non-paper side of the stream. On the paper side of the stream, it cannot entrain the adjacent air into the stream flow because the paper is blocking the air from entraining, so it pulls the paper itself. Then in the next second, the entrained flow on the non-paper side mixes into the stream and increases the pressure there. That should lower the difference between pressure in the stream and pressure around the stream, except that the paper blocks the air on its side of the stream from entraining into the flow, and so the force pulling the paper persists. Add some aluminum, kerosene, and human ingenuity, and you have an A380. Give it a fair try it yourself.
this is a good explanation of Coanda Effect. However, it does not explain lift, because planes with foil wings can fly upside down by changing angle of attack. Angle of attack is underappreciated in lift explanations, because the fuselage of planes also provides lift by angle of attack i.e. Newton.
Well, more angle of attack creates more curvature of the stream of air (untill a certain point) and therefore creates more lift. The video explains all that and definitely explains lift.
@@helicart I'm still not sure where you're going exactly. My answer would be: 1/ let's look at the air flow (smoke lines or computer simulation) around your upside down wing and we'll see that the flow is overall curved 2/ airplanes that can actually fly upside down have symmetrical wings, so both surfaces are curved 3/ the extreme case of what you say would be a wing that looks like a sail, but rigid, and upside down. In that case I believe there would be no Coanda effect (no laminar flow on the concave surface at the top), so indeed only lift from the bottom surface and that seems like a very bad lift. Does that make sense? Still think there is nothing wrong with the video.
@@colinwillis1373 No, all planes designed for upside down flight (Acrobat Sport II) do not have symmetrical foil wings. The AS II has a conventional wing with upper foil and lower flat surface. It is all over youtube flying upside down. The problem with the video is it attributes the bulk of lift to the Coanda effect, which is wrong. The convention is to attribute most lift to the Bernoulli effect, which is also wrong. Angle of attack and Newton's third law are what allow Acro Sport II to fly upside down. If Bernoulli or Coanda effects generated most lift, the plane could not fly upside down. Further, google Alaska Airlines Flight 261. It was a commercial plane that the pilots successfully flew upside down for a short time, while trying to save the plane due to mechanical damage. It's wings are also upper foil only. Academics don't design wings. They postulate and throw theories around without qualifying the contribution of each component of lift, nor spending the time to see what happens in the real world, outside universities. This is intellectual sloth.....but what do they care. They are not actually building planes.
@@helicart you make it sound like Bernoulli and Newton are two different physical phenomena, but in reality they are two sides of the same medal. Newton being more general.
My dear professor...my dear dear professor....there is no flow...there are no streamlines...these things only exist in wind tunnels... I've posed a global challenge if anyone can fully explain creation of lift and bouyancy. I humbly invite you to also take part and solve these yet unfolded mysteries.
How does your explanation distinguish between the flow around a hydrofoil in liquid helium compared to the same hydrofoil in liquid sodium with identical geometry or kinematics?
What about Newton’s 3rd law and the change of momentum in the flow direction…Action/Reaction? I don’t see much of an angle of attack in his flow diagrams…Partial explanation?
@@grahamj9101 since then I’ve done a good bit of reading and rather than the third law, now focussing more on the second law where the wing imparts a downward vector on the airflow while conserving the energy mass and momentum. There are real world examples of what you are looking for….Watch airplanes enter cloud and see what happens to the cloud beneath the airplane.
@@dronemonkey2038 As a STEM Ambassador, I use photos of aircraft flying just above the cloud tops to show the very obvious 'downwash' produced by a wing, when discussing the generation of with primary school level students.
along any given streamline, you can use Bernoulli. But to explain the Lift, you must look at the pressure gradient Across multiple streamlines (which is something Bernoulli's Principle cannot do).
As an engineer with a lifelong interest in flight, I'd puzzled over how a wing really worked for years. Then, some years ago, came up with a hypothesis with which I was satisfied - only to discover that Prof Babinsky had beaten me to it! However, I have one issue that even Prof Babinsky and many others fail to addresss. Lift is explained in terms of moving air flowing over a stationary wing, as in a wind tunnel. However, that is not what happens in the 'real world', where a moving aerofoil displaces previously stationary air. We need a 'real world' model of this, showing the downward displacement of air after the passage of a wing, which must also have a small forward component. For a 'real world' example, please take a look at any one of several photos or videos of aircraft flying just above the cloud tops.
It makes no difference whether the frame of reference is the wing, as in a wind tunnel, or the freestream, as in an airplane in flight, or any other frame of reference you care to choose so long as it is an inertial frame of reference. If the theoretical model works in one frame, it works in all frames.
@@XPLAlN Of course, the theoretical model works whatever, in terms of the wing producing lift. However, I repeat my previous contention. If you wish to understand what happens to the air in the real world, once the wing has done its stuff, then the wing needs to be moving, not the air. For example, have you ever viewed the films of tests that NASA did back in the 1970s, aimed at investigating the effect and persistence of wingtip vortices?
@@grahamj9101 ok you are making the assumption that few, if any people in the industry, are aware of wingtip vortices. It's just 'you and NASA'. This is a fallacy. Vortices get a lot of attention because they are a large source of drag as well as a significant hazard. I totally agree that vortices have to be modelled in order to get a good understanding of how the airfoil is going to perform in the real world. But I am disagreeing with your belief that this is not addressed in the industry. Every undergraduate aeronautical engineer will learn about vortices. Even professional pilots will learn about the nature and effects of vortices. But learning this stuff starts with 2d flow, as in studying the airflow in cross section. Only after that is the 3d stuff introduced.
@@XPLAlN I certainly did not suggest that few, if any in industry are aware of wingtip vortices. However, how many of Babinski's audience that evening would have appreciated the fact that the movements in the flow of air downstream of a stationary wing (as in a wind tunnel) must be very different from the movements in a previously stationary body of air through which a wing has just passed? Babinski considers it important for the wider public (such as sixth formers and even airline pilots) to understand that the 'flow' over the upper surface of a wing arrives at the trailing edge sooner than the 'flow' beneath the wing, in order for them to have a correct understanding of the generation of lift. I have, by the way, put the word flow in inverted commas because, in the case of a wing moving through stationary air, there is no actual flow. What I am suggesting is that the wider public should also be educated in the difference between a stationary wing in a moving airflow and a moving wing passing through a stationary body of air. My intention was to suggest that the films of the work that NASA did in the 1970s are a graphic illustration of this, which needs to be more widely understood.
Errata?: Cows are blown UP just outside the low pressure eye of violent spiralling winds, according to Researchers with Cameras. More to do with tangential momentum and Ground Effect than "suction", they say?
Very interesting and probably right up the ally of some nerds in aerodynamics. For the operational pilot flying a normal standard commercial plane his every day job is still to find that alpha that will give him a straight flightpath where lift balances out the mass+the taildown force for the velocity he cruises at regardless of any more or less correct way of explaining the "true" way lift is produced What I'm trying to say is that Prof. Babinsky's explanation - no matter how good and correct it is - will not provide the pilot with anything more useful than what the "old" explanations did.
(15:17) By hanging the sheet of paper vertically, the downward STATIC pressure gradient due to GRAVITY is no longer providing that differential in pressure on the ground facing side of a horizontal planal surface. Gravity's effect on a fluid like air is the prerequisite of lift !! How counterintuitive. (46:30) By the same reasoning, wouldn't the thicker aerofoil would generate less lift in this airstream profile because the convex bottom surface is accelerating the airflow a neutralizing the effect of the contrast in pressure between upper and lower surfaces if the aerofoil? Ah, paragliders, of course. (54:00) The spinning ball in the airstream. American baseball pitchers take advantage of this aerodynamic effect to keep batters from any contact on the baseballs that are hurled toward home plate.
The "downward STATIC pressure gradient " is so small to be completely irrelevant -- and I don't even see how it could have an effect. . Coanda produces a lowered pressure along a convex surface. That is what *starts* the paper rising. . This is for the same reason that a flow produces a pressure rise along a concave surface. Here's part of the answer: The physics of flow along a convex surface: ruclips.net/video/3MSqbnbKDmM/видео.html
Since my original comment below, another thought has struck me: Prof Babinski makes a point of neglecting friction in his explanation of the generation of lift. However, do I recall being taught (and reading in the various books, which I have collected over the years, in order to arrive at an understanding of lift) that, in an inviscid flow, where there can be no drag, there can also be no lift? Prof Babinski demonstrated the generation of lift by a rotating cylinder (the Magnus effect) in his little vertical wind tunnel. However, a rotating cylinder (or spinning football) clearly relies on friction to create the asymmetric flow condition. Should he not have addressed this?
For a wing, an inviscid flow can have the came flow pattern. Also, friction, actually viscosity, is not required for a flow to follow a convex curved surface. Don't forget that the atmospheric pressure that we don't feel is still there pushing itself against all surfaces. .. Hold up your hand like STOP. The front of that hand has about 300 pounds of force from air pressure. Stand up and there is about 12,000 pounds on your front. A Cessna 172 has about 350,000 pounds on its wing's upper surface. .. That pressure does not go away just because something moves. .. .. Professor Krzysztof Fidkowski, associate professor, Aerospace Engineering University of Mich mentions this about inviscid flow. How Planes Fly. *ruclips.net/video/aa2kBZAoXg0/видео.html: ...
lift can exist in a theoretically frictionless environment. friction is merely a matter of efficiency. the total lift you get by neglecting friction, will be more than you'll actually get in real life when friction applies.
You mean by friction the propriety of viscosity in real fluids, and yes you are correct in frictionless world of fluid dynamics the flow around what ever shape of body will be "irrotational" and no forces will be generated(drag/lift).
According to the video, the lecture was presented in 2003. A number of years ago, I ran across this video on RUclips, but the images were in a pdf file and it was hard to follow so all I did was create a video with the images as part of the video. I know nothing to speak of regarding this subject.
Phil White thank you for posting this. It certainly brings back memories and I think I will write to Dr Babinsky this Christmas, he may not remember me but he plays a big part in my life.
Coanda and friction are not required for lift. There are pretty of potential flows, (airfoils, rotating cylinders) which are by definition inviscid that generate plenty of lift. As Babinsky correctly explains, It is the turning of the flow that causes lift.
@@iltgdellosportivo2066 The best explanation I’ve seen is quite lengthy but it comes down to an interplay between the pressure and velocity. Any lengthy summary here wouldn’t do it justice so I’ll refer you to Doug McLean’s Understanding Aerodynamics Arguing from the Real Physics. You should be able to find the PDF online.
The authors have two wrong scientific approaches: researching the creation of Lift force and Low pressure at upper side of the wing, relative to the ground surface and Earth. I explain the aerodynamic cavitation and existence of Lee side aerocavern, and creation of Aerodynamic force.
Babinsky is wrong. It is not the curvature that causes the low pressure. The streamlines are curved to navigate the physical object in the flow, each streamline formed by the mass boundary of surrounding streamlines, since the flow is incompressible. Streamlines are constricted in x section thickness due to the physical obstruction of the solid wing, thus by Bernoulli, streams have increased velocity and dynamic pressure, and this is what causes the low pressure. In theory, this would mean the streamlines under the wing would have high dynamic pressure and low static pressure as well, and by C effect turn around the trailing edge of the wing onto the upper surface of the wing where the rear stagnation point of the flow around the wing should be. In theory, resulting in zero lift. However, due to viscousity of the fluid, boundary layer seperation occurs very soon after the BL navigates around the sharp trailing edge, changing the flow geometry. This effect is same as having a vortex around the aerofoil, or as demostrated, a cylinder spinning. The reaction to this vortex is a torque opposite to the angle of attack acting on the wing. This is the ONLY action reaction pair in the system! The flow under the wing wants to turn around the trailing edge, but is forced to carry on in the observed geometry under the influence of the vortex generated by the wing. As a result, once stable flow is achieved, the under wing streamlines are far less restricted in x section thickness and have high static pressure. This is the real way lift is created. The fat wing has a weaker vortex because its trailing edge is less sharp
This is just the ramblings of a man who has been in the theoretical side of things for too long. There is a reason why aircraft tend to require a large velocity in flight.
Babinsky is wrong. About the curvature and the blowing paper demonstration. The reason why the paper doesnt move in the vertical scenario is because the paper is already in contact with the stream. Repeat the demonstration with perfectly flat paper and a fan, and different angles with respect to starting angle of the flat paper and the paper will always lift towards the boundary of the moving airstream until in contact with the stream
No.. You are mistaken. That downward blowing thing is misleading and, therefore, a bad demo unless done correctly. If you blow not-in-contact, that stream of air is not in contact . That stream does NOT have a lower pressure than atmospheric.
@@Observ45eryou are somewhat correct, in fact the air in front of the fan will be at a slightly higher pressure than the surrounding air, otherwise it wouldn't push the air further in front forwards. If the air in front of the fan didn't push the air in front forwards, the fan would build an accumulation of air in front of it that is at the same pressure as the surrounding air. Hands up anyone who believes that is possible!
@@kingsleydyson4841 Well, yes, but that is in the start-up transient phase people rarely discuss, nor even understand less than the steady state.. . The air from the fan also has mass and inertia, so the dynamic pressure moves the leading edge out. However, once the flow is established, that isn't needed. Thereafter, in the steady state, is the entrainment around the flow and the boundary turbulence. . . . . But you seem to have made an error here: "If the air in front of the fan didn't push the air in front forwards, the fan would build an accumulation of air in front of it that is at the same pressure as the surrounding air." This is contradictory: "build an accumulation of air ... at the same pressure as the surrounding air" If it was an "accumulation", it would be at a higher pressure. . Blowing above the paper is Coanda followed by entrainment. . And Truckie is incorrect because with the flow directed at various angles, there is no lift. I demo that very thing.
Babinsky is wrong. A streamline is flow restricted that particular path by conditions and forces external to that streamline. Curvature does not generate low pressure, the C effect is because a solid surface has no pressure. You can tell an explanation or a path of reasoning is suspect if the phrase "there must be" gets thrown around, it is a statement of speculation
Babinsky is correct. All the other lift video authors need to study him. .. You are mistaken, but seem to understand that the surface does impose an additional constraint. The key is understanding the relationship of the flow direction to the surface direction. . The surface must have the very same "pressure" as the air against it. It is not zero. If it was zero, the atmospheric pressure would be thousands of pounds of force downward on the top of the wing. At 14 psi a Cessna wing with 25,000 square inches of wing area has 350,000 pounds of DOWNWARD force due to air pressure!
@@SoloRenegade read this: How the Coanda Effect Works. When you squirt a jet of fluid (could be water, could be air, could be most liquids or gases, they are all fluids) into a large body of non-moving fluid, that jet of fluid will start to interact with the big stationary body of fluid. It will start to mix with it and start to move it along too. Think of a water jet coming out of the wall of a Jacuzzi. If you hold your hand in front of the opening, you feel a small concentrated blast of high speed water. If you hold your hand further away, you feel a broader region of water moving more slowly. If you hold your hand even farther away, you feel a general flow of all the water in the region. This interaction with stationary fluid is what the Coanda effect is all about. That is absent in the flow over a wing (and don’t give me any BS about the boundary layer on the wing being slow moving fluid - that’s almost the inverse of what is happening here. And it’s certainly not present in potential flow). So this narrow jet of high speed fluid is emerging from the nozzle and is surrounded by stationary fluid. By viscous stresses and turbulent mixing, it drags along some of that stationary fluid and gets it moving too. That is, it speeds up a layer of fluid next to itself. By reaction (Newton, you know) that slows down the fluid in the jet. After all, momentum is conserved. So the fast moving narrow jet starts to broaden into a wider jet of slower moving fluid. But it’s dragging that fluid along from somewhere. It’s moving it away from where it started. That leaves a sort of hole behind. That fluid that is removed has to be replaced. It sucks in fluid laterally from farther away from the jet. This keeps happening all along the length of the jet. More and more fluid is being pushed along and therefore more and more fluid has to be sucked in from the sides. Later on, I’ll try and find some photographs showing this effect, which is called entrainment. The jet entrains surrounding fluid. That just means it sucks it in from the sides and shoves it forward. This sucking inward of surrounding fluid - that is what causes the Coanda effect. Note that I have not mentioned any walls yet, curved or otherwise. I’ve just talked about a jet of fluid sucking in surrounding fluid. What happens if we block that inward flow of the surrounding fluid by putting a wall on one side near the jet? The wall is parallel to the direction the jet is moving. This wall can be straight. No need for any curved surfaces. The curved surfaces that are associated with many descriptions of the Coanda effect are just distractions. There is no need for the surface to be curved for the Coanda effect to work. All you need is a jet of fluid that is trying to suck in the surrounding fluid and a wall that blocks that flow of fluid towards the jet. Actually, you don’t even need a wall. Two jets flowing side by side will each suck towards the other one as though there were a wall between them. That’s still the Coanda effect. So what happens? The jet can’t pull fluid in from that direction where the wall is, but the suction effect that would have pulled that fluid in from that side still exists. It’s a low pressure region. Instead it pulls the jet over to that wall. The jet deflects over towards the wall and then flows along the wall. It’s doing that because it’s trying to entrain the fluid over there and it can’t. It’s only creating the suction effect because it is accelerating fluid that is not moving and getting it going in the direction of the jet. It’s entraining fluid. Or trying to. So the jet sucks itself over to the wall and then runs along the wall. Mind you, it’s still entraining fluid from the other sides of the jet. None of this entrainment occurs with a wing because all the air is already moving at essentially the same speed. There is no mixing with stagnant fluid. There is none of this sucking in of fluid that is replacing fluid that has been entrained by the jet. There is no jet. All the air is moving. There just happens to be this curved surface (the top of the wing). It vaguely looks like the description of the Coanda effect. But there’s no Coanda effect. Sorry, there’s just confusion. And belief. And proselytizing. It’s amazing how strongly some people will hold to their belief based on a misunderstanding of the underlying physics.
@@MrJackjr7 the problem is, all the air a wing moves through is stationary, their is no jet..... Also, Coanda effect is created in multiple ways with no jet of air, which you failed to explain as well.
Sorry prof but you have got it wrong. When you blew across the flat paper the paper it did not move towards the faster flowing air because the energy to accelerate the air came from you not the surrounding air so the air pressure did not fall. Bernoulli’s theorem states that the acceleration of the air is a transfer of energy from the surrounding air. Which is why the pressure falls. Bernoulli’s theory explains flight.
Garbage.. totally overlooked shear forces and their gradient due to boundary layer, across the finite fluid cube R8 approach is treat airfoil as 1/2 venturi & use velocity gradient within boundary layer to model pressure drop at top surfaces v bottom surface
![Gunna - back in the a [Official Video]](http://i.ytimg.com/vi/oBrbejOHjLw/mqdefault.jpg)
WOW, I have been an airline pilot fo 40 years, and I finally get it!
Best talk ever. A well-know Brazilian RUclipsr, called Lito Sousa, from Aviões e Músicas, made a resumed explanation, using the same exampled of yours.
This truly shows the potention of accurate, clearly-explained scienctific info, and I'd like to thank you.
Your work product is to be commended worldwide.
Awesome, all my respect
Brilliant explanation indeed! Congrats 🎉
Great simple presentation of a complex matter. Well done!
Splendid!
I'm 15 years and English isn't my first language, but I understood every word. Professor is explanating really simple and easy to understand
THANK YOU!!!!
Babinsky is wrong, there is a constant for Bernoulli in a system open to the atmosphere: it is atmospheric pressure. The flow generated by the hairdryer has kinetic energy, but its total pressure is still atmospheric pressure. Static pressure inside the flow is much lower than atmospheric pressure. This is how carburetors work.
Explain……
@@letsgo1153 he can't, he doesn't know what he's talking about.
awesome explanation!
excellent!!
Professor H. Babinsky explains curvature generates pressure difference that is the source of the lift. It is applicable to the sail, the heeled hull, and and the keel. In addition, it is also applicable to the rotor ship with the spinning cylinder. Shape generates function, indeed.
39:05 I don't agree, when you pour a liquid and some of it runs down the side of the container is because of adhesion. If it was the coanda effect, it would increase when pouring faster.
babinksy sensei 😔🤞
!! omg glad to see i’m not the only babinsky stan
omfg we all lifting
almost forgot to watch this today
v helpful video today babin !🥰
im so happy our sweet little babinsky gets the attention he deserves 💕
It's a crystal clear explanation.. Amazing sir
No !
@@synergy6294 It is correct, but a little limited. He doesn't explain just how those pressure changes are caused.
The full physics is not too difficult, but so many others don't understand the simple physics of the causes.
This is crystal clear ...chk tekemon
@@Observ45er how are the pressure changes caused? Sorry, I need to know this for a project of mine.
The illustration of the sailboat is incorrect as any sailor can tell you. The air does does not flow over the leeward side of the sail the same way as the windward side. If it did, the sail would merely flap as it does when you head directly into the wind. When the sail is full and trimmed, there are eddies of air close to the leading edge (behind the mast) and the wind rushes over the eddies like it does a wing. You can see this on a sail that has "telltales" (short 6-8 inch pieces of wool yarn) attached to the sail a few feet above the boom in a line from the belly (near the mast) to the leach (the trailing edge) of the sail. The one near the mast will be fluttering all over and sometimes be pointing straight up the sail at twelve o'clock. The rest will hang at progressively higher angles from the vertical to horizontal (6 o'clock to 3 o'clock) as they approach the trailing edge, with the one on the edge streaming straight out to 3 o'clock as you would expect. In fact, a good helmsman will steer and trim the sails watching the telltales to get the most speed out of the boat.
He is just showing a simplified 2d flow to make the point that a sail is like a wing on its side. What you have described is the 3d flow around a real sail. It is only to be expected that tell tales just above the boom will be trailing ‘down’ because the local airflow is trying to get under the boom (ie from high pressure to low pressure side). It is exactly the same concept that gives rise to wing tip vortices.
46:00 minutes
Very nice demonstration of the common bernoulli explanation. On the left we have a fat low resistance foil, and on the left we have a foil that has much more resistance. So, the greater the differential I'm resistance between top and bottom then the greater the flow speed differential and the greater the pressure differential.
Faster flow lower static pressure.
At 23minutes check this out.
ruclips.net/video/zmn7bJvCDn4/видео.html
can u explain why then water rises up in a straw when we blow over the straw? the explanation they give is the air above the straw is moving so it have slower pressure but it seems so flawed
Thank you sir for uploading the video
Nice explanation sir
08:42 a few explanations for why bernoullie application to lift is wrong.
Lecture is from 2003. If you want to know how planes fly here is the dude to listen to; NOT NdGT! 😎
Please share the download link which was discussed in the beginning of the video.
The "Rubber Sheet" explanation of Gravity using Gravity = Negative Lift, is a similar pattern of discovery of a specific Form in Function, by "design" = frequency density-intensity alignment of "conducting" resonance-location cofactors in prime superposition, ie "Form follows Function" and e-Pi-i sync-duration connectivity function operates on itself, "module-ates", self-defining Real-time Number substantiation.
A consequence of this proof-disproof in Theoretical Design Testing, is that the explanation of Observable Actuality Conception is the reference-framing pure-math relative-timing ratio-rates-> Circuitry of QM-TIME, instantaneous "creation" condensation-quantization = Quantum pure-math-fields oscillation, ..axial-tangential @.dt zero-infinity orthogonality sync-duration, for superposition resonances-> net vector-values temporal superposition apparent "flow", and the cause-effect omnidirectional-dimensional information-pressure, which is Fractal Quantum Operator Logic Fields Modulation Mechanism, ..at the Centre of Time Duration Timing Singularity.., aka Inflation, Gravity, line-of-sight frequency superposition, because frequency aligned-> Cofactor Conduction, radial projection-drawing holographic phenomena such as density-intensity real-numberness condensation modulation matter, and so on.
Reciproction-recirculation Singularity synthesises an AM-FM holographic 0-1-2-ness 3D-T pictorial image, by e-Pi-i log-antilog interference.., so
=> allowing the Rubber Sheet to represent the plasticity of functional-temporal logarithmic hyperfluid vertices in vortices, lifted = floating or levitating, apparently on nothing, actually embedded in Superspin-foam Temporal Totality.
Putting things in perspective, 0-1-2-ness line-of-sight Fluxion-Integral superposition =i-reflection on the picture-plane projection-drawing image containment.., makes the balanced orthogonal-normal pure-math relative-timing ratio-rates Equation in the Holographic Principle Imagery, a bit more interesting. Especially if you begin with the Calculus of Logarithmic Time Condensation Communication here-now-forever. Resonance is a very simple concept to grasp Mathematically-Musically, in a fractal AM-FM conic-cyclonic Centre of Time Duration Timing Conception way..
14:22
His debunking of the photocopier paper experiment is itself bunk. When he holds it down, he tensions the paper in such a way that the Bernoulli effect can't work it. It might have just as well been a sheet of cardboard. If you hold a sheet of paper vertical to the earth (from which most gravity comes) and allow it enough flexibility to sway, then the experiment proves Bernoulli.
As the forced air stream moves downward, it entrains higher pressure air into the flow on the non-paper side of the stream. On the paper side of the stream, it cannot entrain the adjacent air into the stream flow because the paper is blocking the air from entraining, so it pulls the paper itself. Then in the next second, the entrained flow on the non-paper side mixes into the stream and increases the pressure there. That should lower the difference between pressure in the stream and pressure around the stream, except that the paper blocks the air on its side of the stream from entraining into the flow, and so the force pulling the paper persists. Add some aluminum, kerosene, and human ingenuity, and you have an A380.
Give it a fair try it yourself.
this is a good explanation of Coanda Effect.
However, it does not explain lift, because planes with foil wings can fly upside down by changing angle of attack.
Angle of attack is underappreciated in lift explanations, because the fuselage of planes also provides lift by angle of attack i.e. Newton.
Well, more angle of attack creates more curvature of the stream of air (untill a certain point) and therefore creates more lift. The video explains all that and definitely explains lift.
@@colinwillis1373
Now turn a plane upside down, and explain how your curved upper wing surface (now facing downwards) creates most of the lift
@@helicart I'm still not sure where you're going exactly. My answer would be:
1/ let's look at the air flow (smoke lines or computer simulation) around your upside down wing and we'll see that the flow is overall curved
2/ airplanes that can actually fly upside down have symmetrical wings, so both surfaces are curved
3/ the extreme case of what you say would be a wing that looks like a sail, but rigid, and upside down. In that case I believe there would be no Coanda effect (no laminar flow on the concave surface at the top), so indeed only lift from the bottom surface and that seems like a very bad lift.
Does that make sense? Still think there is nothing wrong with the video.
@@colinwillis1373
No, all planes designed for upside down flight (Acrobat Sport II) do not have symmetrical foil wings. The AS II has a conventional wing with upper foil and lower flat surface. It is all over youtube flying upside down.
The problem with the video is it attributes the bulk of lift to the Coanda effect, which is wrong.
The convention is to attribute most lift to the Bernoulli effect, which is also wrong.
Angle of attack and Newton's third law are what allow Acro Sport II to fly upside down. If Bernoulli or Coanda effects generated most lift, the plane could not fly upside down.
Further, google Alaska Airlines Flight 261.
It was a commercial plane that the pilots successfully flew upside down for a short time, while trying to save the plane due to mechanical damage. It's wings are also upper foil only.
Academics don't design wings. They postulate and throw theories around without qualifying the contribution of each component of lift, nor spending the time to see what happens in the real world, outside universities. This is intellectual sloth.....but what do they care. They are not actually building planes.
@@helicart you make it sound like Bernoulli and Newton are two different physical phenomena, but in reality they are two sides of the same medal. Newton being more general.
So, the lift could be explained without using Bernoulli and only by Coanda effect?
will the coanda effect work in a vacuum? if yes why?
air go down plane go up
Considering the big picture, is Newton's perspective sufficient?
My dear professor...my dear dear professor....there is no flow...there are no streamlines...these things only exist in wind tunnels...
I've posed a global challenge if anyone can fully explain creation of lift and bouyancy. I humbly invite you to also take part and solve these yet unfolded mysteries.
How does your explanation distinguish between the flow around a hydrofoil in liquid helium compared to the same hydrofoil in liquid sodium with identical geometry or kinematics?
it doesn't, it works the same. and it's not his explanation. he reposted Bakinsky's lecture with the slides added for better context.
What about Newton’s 3rd law and the change of momentum in the flow direction…Action/Reaction? I don’t see much of an angle of attack in his flow diagrams…Partial explanation?
Please see the comment that I've just posted.
@@grahamj9101 since then I’ve done a good bit of reading and rather than the third law, now focussing more on the second law where the wing imparts a downward vector on the airflow while conserving the energy mass and momentum. There are real world examples of what you are looking for….Watch airplanes enter cloud and see what happens to the cloud beneath the airplane.
@@dronemonkey2038 As a STEM Ambassador, I use photos of aircraft flying just above the cloud tops to show the very obvious 'downwash' produced by a wing, when discussing the generation of with primary school level students.
I agree with you on the change of momentum… Look for video by Fidkowski for a very good explanation also.
Probbaly i missed something. How the curvature explain the faster airspeed can produce more lift?
along any given streamline, you can use Bernoulli. But to explain the Lift, you must look at the pressure gradient Across multiple streamlines (which is something Bernoulli's Principle cannot do).
Who would give this a thumbs down?
It could've been due to not agreeing with certain things.
Or hating the way the video was cut.
Or it's quality.
try to blow in between 2 pieces of papers that are vertical and parallel, close to each other see what happens
You push more air molecules into the gap causing a separation.
The amount of "we don't need to worry about that"s concern me.
basically whole phicis is boiling down and simplification as much as possible while is still good enough....
Please watch this RUclips playlist ruclips.net/p/PLduPQKjH6QXT7sSsvfhQ31cRB0S9QN4nj.
Flat wings(whitout curvature)produce lift why?
Flat wings also curve the stream of air down (but not as nicely as curved wings for sure)
As an engineer with a lifelong interest in flight, I'd puzzled over how a wing really worked for years. Then, some years ago, came up with a hypothesis with which I was satisfied - only to discover that Prof Babinsky had beaten me to it!
However, I have one issue that even Prof Babinsky and many others fail to addresss.
Lift is explained in terms of moving air flowing over a stationary wing, as in a wind tunnel. However, that is not what happens in the 'real world', where a moving aerofoil displaces previously stationary air.
We need a 'real world' model of this, showing the downward displacement of air after the passage of a wing, which must also have a small forward component.
For a 'real world' example, please take a look at any one of several photos or videos of aircraft flying just above the cloud tops.
It makes no difference whether the frame of reference is the wing, as in a wind tunnel, or the freestream, as in an airplane in flight, or any other frame of reference you care to choose so long as it is an inertial frame of reference. If the theoretical model works in one frame, it works in all frames.
@@XPLAlN Of course, the theoretical model works whatever, in terms of the wing producing lift. However, I repeat my previous contention. If you wish to understand what happens to the air in the real world, once the wing has done its stuff, then the wing needs to be moving, not the air.
For example, have you ever viewed the films of tests that NASA did back in the 1970s, aimed at investigating the effect and persistence of wingtip vortices?
@@grahamj9101 ok you are making the assumption that few, if any people in the industry, are aware of wingtip vortices. It's just 'you and NASA'. This is a fallacy. Vortices get a lot of attention because they are a large source of drag as well as a significant hazard. I totally agree that vortices have to be modelled in order to get a good understanding of how the airfoil is going to perform in the real world. But I am disagreeing with your belief that this is not addressed in the industry. Every undergraduate aeronautical engineer will learn about vortices. Even professional pilots will learn about the nature and effects of vortices. But learning this stuff starts with 2d flow, as in studying the airflow in cross section. Only after that is the 3d stuff introduced.
@@XPLAlN I certainly did not suggest that few, if any in industry are aware of wingtip vortices.
However, how many of Babinski's audience that evening would have appreciated the fact that the movements in the flow of air downstream of a stationary wing (as in a wind tunnel) must be very different from the movements in a previously stationary body of air through which a wing has just passed?
Babinski considers it important for the wider public (such as sixth formers and even airline pilots) to understand that the 'flow' over the upper surface of a wing arrives at the trailing edge sooner than the 'flow' beneath the wing, in order for them to have a correct understanding of the generation of lift. I have, by the way, put the word flow in inverted commas because, in the case of a wing moving through stationary air, there is no actual flow.
What I am suggesting is that the wider public should also be educated in the difference between a stationary wing in a moving airflow and a moving wing passing through a stationary body of air.
My intention was to suggest that the films of the work that NASA did in the 1970s are a graphic illustration of this, which needs to be more widely understood.
Relativity. makes NO differnce. and some aircraft DO fly by moving the air over the wing. Custer Channelwing would be exhibit A.
He looks happy enough in the thumbnail, I don't think he need s a lift.
Errata?: Cows are blown UP just outside the low pressure eye of violent spiralling winds, according to Researchers with Cameras.
More to do with tangential momentum and Ground Effect than "suction", they say?
there is not much of a curve to an f104's wing!!! - i wonder if the principals change above mach1
Very interesting and probably right up the ally of some nerds in aerodynamics. For the operational pilot flying a normal standard commercial plane his every day job is still to find that alpha that will give him a straight flightpath where lift balances out the mass+the taildown force for the velocity he cruises at regardless of any more or less correct way of explaining the "true" way lift is produced
What I'm trying to say is that Prof. Babinsky's explanation - no matter how good and correct it is - will not provide the pilot with anything more useful than what the "old" explanations did.
🙊whaaaat…
Operating a machine without clear understanding of its principles…🙈
@@FofXequalsYnot clear understanding yes - scientific explanation? overkill
(15:17) By hanging the sheet of paper vertically, the downward STATIC pressure gradient due to GRAVITY is no longer providing that differential in pressure on the ground facing side of a horizontal planal surface.
Gravity's effect on a fluid like air is the prerequisite of lift !! How counterintuitive.
(46:30) By the same reasoning, wouldn't the thicker aerofoil would generate less lift in this airstream profile because the convex bottom surface is accelerating the airflow a neutralizing the effect of the contrast in pressure between upper and lower surfaces if the aerofoil? Ah, paragliders, of course.
(54:00) The spinning ball in the airstream. American baseball pitchers take advantage of this aerodynamic effect to keep batters from any contact on the baseballs that are hurled toward home plate.
The "downward STATIC pressure gradient " is so small to be completely irrelevant -- and I don't even see how it could have an effect.
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Coanda produces a lowered pressure along a convex surface. That is what *starts* the paper rising.
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This is for the same reason that a flow produces a pressure rise along a concave surface.
Here's part of the answer:
The physics of flow along a convex surface:
ruclips.net/video/3MSqbnbKDmM/видео.html
Since my original comment below, another thought has struck me: Prof Babinski makes a point of neglecting friction in his explanation of the generation of lift.
However, do I recall being taught (and reading in the various books, which I have collected over the years, in order to arrive at an understanding of lift) that, in an inviscid flow, where there can be no drag, there can also be no lift?
Prof Babinski demonstrated the generation of lift by a rotating cylinder (the Magnus effect) in his little vertical wind tunnel. However, a rotating cylinder (or spinning football) clearly relies on friction to create the asymmetric flow condition.
Should he not have addressed this?
For a wing, an inviscid flow can have the came flow pattern. Also, friction, actually viscosity, is not required for a flow to follow a convex curved surface.
Don't forget that the atmospheric pressure that we don't feel is still there pushing itself against all surfaces.
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Hold up your hand like STOP. The front of that hand has about 300 pounds of force from air pressure. Stand up and there is about 12,000 pounds on your front. A Cessna 172 has about 350,000 pounds on its wing's upper surface.
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That pressure does not go away just because something moves.
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Professor Krzysztof Fidkowski, associate professor, Aerospace Engineering University of Mich mentions this about inviscid flow.
How Planes Fly. *ruclips.net/video/aa2kBZAoXg0/видео.html:
...
lift can exist in a theoretically frictionless environment. friction is merely a matter of efficiency. the total lift you get by neglecting friction, will be more than you'll actually get in real life when friction applies.
You mean by friction the propriety of viscosity in real fluids, and yes you are correct in frictionless world of fluid dynamics the flow around what ever shape of body will be "irrotational" and no forces will be generated(drag/lift).
44:22
I had the honour to be taught by this gentleman 20 years ago. When was this taken?
Sorry, 2003.
According to the video, the lecture was presented in 2003. A number of years ago, I ran across this video on RUclips, but the images were in a pdf file and it was hard to follow so all I did was create a video with the images as part of the video. I know nothing to speak of regarding this subject.
Phil White thank you for posting this. It certainly brings back memories and I think I will write to Dr Babinsky this Christmas, he may not remember me but he plays a big part in my life.
He is wrong though. When he begins the lecture with that tiny wind tunnel with obvious wall effects, I totally face palmed
@@VicAusTaxiTruckie would you mind expanding on this please?
Basically a wing is like WATER SKI. just the upper surface has to be aerodynamic, so there is no rotor on the upper side.
He didn't explain how coanda effect works, it s half part of all, first you have to demonstrate coanda, but for that you have to introduce friction
Coanda and friction are not required for lift. There are pretty of potential flows, (airfoils, rotating cylinders) which are by definition inviscid that generate plenty of lift. As Babinsky correctly explains, It is the turning of the flow that causes lift.
Coanda effect does not work in airfoils !!!!!!!
Please share the download link which was discussed in the beginning of the video
@@aerohakai5871 yes but why does the flow turn?
@@iltgdellosportivo2066 The best explanation I’ve seen is quite lengthy but it comes down to an interplay between the pressure and velocity. Any lengthy summary here wouldn’t do it justice so I’ll refer you to Doug McLean’s Understanding Aerodynamics Arguing from the Real Physics. You should be able to find the PDF online.
The authors have two wrong scientific approaches: researching the creation of Lift force and Low pressure at upper side of the wing, relative to the ground surface and Earth. I explain the aerodynamic cavitation and existence of Lee side aerocavern, and creation of Aerodynamic force.
all the paper airplanes i made as a kid disagree with you
Wrong. many paper airplanes have a crude curved airfoil, but the AOA is what creates curvature in the airflow as well.
Babinsky is wrong. It is not the curvature that causes the low pressure. The streamlines are curved to navigate the physical object in the flow, each streamline formed by the mass boundary of surrounding streamlines, since the flow is incompressible.
Streamlines are constricted in x section thickness due to the physical obstruction of the solid wing, thus by Bernoulli, streams have increased velocity and dynamic pressure, and this is what causes the low pressure.
In theory, this would mean the streamlines under the wing would have high dynamic pressure and low static pressure as well, and by C effect turn around the trailing edge of the wing onto the upper surface of the wing where the rear stagnation point of the flow around the wing should be. In theory, resulting in zero lift.
However, due to viscousity of the fluid, boundary layer seperation occurs very soon after the BL navigates around the sharp trailing edge, changing the flow geometry. This effect is same as having a vortex around the aerofoil, or as demostrated, a cylinder spinning. The reaction to this vortex is a torque opposite to the angle of attack acting on the wing. This is the ONLY action reaction pair in the system!
The flow under the wing wants to turn around the trailing edge, but is forced to carry on in the observed geometry under the influence of the vortex generated by the wing. As a result, once stable flow is achieved, the under wing streamlines are far less restricted in x section thickness and have high static pressure.
This is the real way lift is created.
The fat wing has a weaker vortex because its trailing edge is less sharp
wrong. turbulent air at teh trailing edge doesn't create lift.
This is just the ramblings of a man who has been in the theoretical side of things for too long.
There is a reason why aircraft tend to require a large velocity in flight.
Babinsky is wrong. About the curvature and the blowing paper demonstration. The reason why the paper doesnt move in the vertical scenario is because the paper is already in contact with the stream. Repeat the demonstration with perfectly flat paper and a fan, and different angles with respect to starting angle of the flat paper and the paper will always lift towards the boundary of the moving airstream until in contact with the stream
No.. You are mistaken. That downward blowing thing is misleading and, therefore, a bad demo unless done correctly. If you blow not-in-contact, that stream of air is not in contact .
That stream does NOT have a lower pressure than atmospheric.
@@Observ45eryou are somewhat correct, in fact the air in front of the fan will be at a slightly higher pressure than the surrounding air, otherwise it wouldn't push the air further in front forwards. If the air in front of the fan didn't push the air in front forwards, the fan would build an accumulation of air in front of it that is at the same pressure as the surrounding air.
Hands up anyone who believes that is possible!
@@kingsleydyson4841 Well, yes, but that is in the start-up transient phase people rarely discuss, nor even understand less than the steady state..
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The air from the fan also has mass and inertia, so the dynamic pressure moves the leading edge out. However, once the flow is established, that isn't needed.
Thereafter, in the steady state, is the entrainment around the flow and the boundary turbulence.
. . . .
But you seem to have made an error here:
"If the air in front of the fan didn't push the air in front forwards, the fan would build an accumulation of air in front of it that is at the same pressure as the surrounding air."
This is contradictory: "build an accumulation of air ... at the same pressure as the surrounding air"
If it was an "accumulation", it would be at a higher pressure.
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Blowing above the paper is Coanda followed by entrainment.
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And Truckie is incorrect because with the flow directed at various angles, there is no lift. I demo that very thing.
This still does not explain how a paper plane flys which have completely flat wings, any help??
many paper airplanes have a crude curved airfoil, but the AOA is what creates curvature in the airflow as well.
Babinsky is wrong. A streamline is flow restricted that particular path by conditions and forces external to that streamline. Curvature does not generate low pressure, the C effect is because a solid surface has no pressure.
You can tell an explanation or a path of reasoning is suspect if the phrase "there must be" gets thrown around, it is a statement of speculation
Babinsky is correct. All the other lift video authors need to study him.
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You are mistaken, but seem to understand that the surface does impose an additional constraint.
The key is understanding the relationship of the flow direction to the surface direction.
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The surface must have the very same "pressure" as the air against it. It is not zero. If it was zero, the atmospheric pressure would be thousands of pounds of force downward on the top of the wing.
At 14 psi a Cessna wing with 25,000 square inches of wing area has 350,000 pounds of DOWNWARD force due to air pressure!
He is wrong.
prove it.
all was good until i hear about COANDA EFFECT , that effect does not apply to airfoils !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
yes it does. they are the same effect
@@SoloRenegade nop, you cant explain why the air sticks to the airfoil using coanda effect, its a fact
@@MrJackjr7 explain it....
@@SoloRenegade read this: How the Coanda Effect Works.
When you squirt a jet of fluid (could be water, could be air, could be most liquids or gases, they are all fluids) into a large body of non-moving fluid, that jet of fluid will start to interact with the big stationary body of fluid. It will start to mix with it and start to move it along too.
Think of a water jet coming out of the wall of a Jacuzzi. If you hold your hand in front of the opening, you feel a small concentrated blast of high speed water. If you hold your hand further away, you feel a broader region of water moving more slowly. If you hold your hand even farther away, you feel a general flow of all the water in the region. This interaction with stationary fluid is what the Coanda effect is all about. That is absent in the flow over a wing (and don’t give me any BS about the boundary layer on the wing being slow moving fluid - that’s almost the inverse of what is happening here. And it’s certainly not present in potential flow).
So this narrow jet of high speed fluid is emerging from the nozzle and is surrounded by stationary fluid. By viscous stresses and turbulent mixing, it drags along some of that stationary fluid and gets it moving too. That is, it speeds up a layer of fluid next to itself. By reaction (Newton, you know) that slows down the fluid in the jet. After all, momentum is conserved. So the fast moving narrow jet starts to broaden into a wider jet of slower moving fluid. But it’s dragging that fluid along from somewhere. It’s moving it away from where it started. That leaves a sort of hole behind. That fluid that is removed has to be replaced. It sucks in fluid laterally from farther away from the jet. This keeps happening all along the length of the jet. More and more fluid is being pushed along and therefore more and more fluid has to be sucked in from the sides. Later on, I’ll try and find some photographs showing this effect, which is called entrainment. The jet entrains surrounding fluid. That just means it sucks it in from the sides and shoves it forward.
This sucking inward of surrounding fluid - that is what causes the Coanda effect. Note that I have not mentioned any walls yet, curved or otherwise. I’ve just talked about a jet of fluid sucking in surrounding fluid.
What happens if we block that inward flow of the surrounding fluid by putting a wall on one side near the jet? The wall is parallel to the direction the jet is moving. This wall can be straight. No need for any curved surfaces. The curved surfaces that are associated with many descriptions of the Coanda effect are just distractions. There is no need for the surface to be curved for the Coanda effect to work. All you need is a jet of fluid that is trying to suck in the surrounding fluid and a wall that blocks that flow of fluid towards the jet. Actually, you don’t even need a wall. Two jets flowing side by side will each suck towards the other one as though there were a wall between them. That’s still the Coanda effect.
So what happens? The jet can’t pull fluid in from that direction where the wall is, but the suction effect that would have pulled that fluid in from that side still exists. It’s a low pressure region. Instead it pulls the jet over to that wall. The jet deflects over towards the wall and then flows along the wall. It’s doing that because it’s trying to entrain the fluid over there and it can’t. It’s only creating the suction effect because it is accelerating fluid that is not moving and getting it going in the direction of the jet. It’s entraining fluid. Or trying to. So the jet sucks itself over to the wall and then runs along the wall. Mind you, it’s still entraining fluid from the other sides of the jet.
None of this entrainment occurs with a wing because all the air is already moving at essentially the same speed. There is no mixing with stagnant fluid. There is none of this sucking in of fluid that is replacing fluid that has been entrained by the jet. There is no jet. All the air is moving. There just happens to be this curved surface (the top of the wing). It vaguely looks like the description of the Coanda effect. But there’s no Coanda effect. Sorry, there’s just confusion. And belief. And proselytizing. It’s amazing how strongly some people will hold to their belief based on a misunderstanding of the underlying physics.
@@MrJackjr7 the problem is, all the air a wing moves through is stationary, their is no jet.....
Also, Coanda effect is created in multiple ways with no jet of air, which you failed to explain as well.
Sorry prof but you have got it wrong. When you blew across the flat paper the paper it did not move towards the faster flowing air because the energy to accelerate the air came from you not the surrounding air so the air pressure did not fall. Bernoulli’s theorem states that the acceleration of the air is a transfer of energy from the surrounding air. Which is why the pressure falls. Bernoulli’s theory explains flight.
Garbage.. totally overlooked shear forces and their gradient due to boundary layer, across the finite fluid cube
R8 approach is treat airfoil as 1/2 venturi & use velocity gradient within boundary layer to model pressure drop at top surfaces v bottom surface