Too many people complaining. This is great. The internet was supposed to be used as an educational tool and I applaud your contribution to the effort. Thanks for this! My prediction for the pipe in reverse is that a low pressure zone will form at the center of the pipe as the air expands with the taper.
@@KlausNietzsche And better yet, we should all be learning each others languages. It is 100x easier to learn a language today than 30 years ago and 1000 easier than 100 years ago. There is a lot lost in translation. We all should be speaking 5-10 languages naturally by the time we are 20. Well, if we were not ruled by criminals, morons, and psychopaths.
@@forrestparsons2378some people are too funny to be taken seriously and them digging their heals about it, makes them appear more helpless and less help able, so you outta time sucka!
@@forrestparsons2378 Что такое ислам? 🔴 Ислам - это не просто еще одна религия 🔵 Это же послание проповедовали Моисей, Иисус и Авраам. 🔴 Ислам буквально означает «покорность Богу». 🔵 и учит нас иметь прямые отношения с Богом. 🔴 Это напоминает нам, что с тех пор, как Бог создал нас, никому нельзя поклоняться, кроме одного Бога. 🔵 Он также учит, что Бог не похож на человека или что-либо, что мы можем вообразить. 🔴 Концепция Бога кратко изложена в Коране как: { Скажи: «Он - Аллах Единый,. Аллах Самодостаточный. Он не родил и не был рожден,. и нет никого равного Ему».} (Коран, 112:1-4) 🔵 Стать мусульманином - это не повернуться спиной к Иисусу. 🔴 Скорее, это возвращение к изначальным учениям Иисуса и повиновение ему...
Yea, it's here 02:09. That said, he's gonna be freaked out this is all decades-old fundamental physics in regard to a parachute design with a central vent hole. Patent Number: 5,360,187 found at nasa.gov He reminds me of my uncle after he's done a few shots of Jack and smoked a bowl.
If this video or channel never used AI to translate the audio AND visuals of this original video to an English video, I probably never would have seen this and possibly never learned this. Politics aside, AI directly allowed me to learn this. That's crazy, and AI is the future. Great video!
Asperger's meets AI. A marriage made in silicon! Just pulling your leg. I found this presentation very interesting and a most excellent use of AI translation. Anything that brings people together and promotes the sharing of knowledge gets my approval. I signed up immediately.
@@TimeSurfer206 I can't wait until you can think of anything in any way funny, interesting or intelligent to add... everyone has a first time- go on, try...
The nice thing about measuring relative pressures is that it's extremely easy to set up a basic yet very accurate differential manometer. All you need is a clear tube, some watter with food dye in it (so you can see it easily) and a board to mount the tube in a U shape. Then you fill it about halfway with the dyed water and connect both ends to the pressure locations you want to compare. Super eaay to build, very visual, very intuitive. Add some line markings and you have a proper instrument 😁
@rickschlosser6793 Usually you're dealing with a few Pa at most, especially when you're playing with vacuum cleaner wind tunnels. So you don't need much length at all 😉
That type of meter is even more.accurate if either tube is at a lower angle. What you cant't directly deduce from that is air flow. You need either static vs dynamic pressure or.air velocity for that. His probe is opposite thae air flow. It's not a true static pressure reading bc Eddy currents, etc, and the deeper.he goes the more the device alters the flow. Good points, though.
@@rickschlosser6793 100kPa isn't much in the grand scheme of things, but I was talking specifically for this demo. This is ram air out of a vacuum cleaner, 100kPa is overkill. For reference, stagnation pressure at 100m/s is just over 6kPa. Outside of going compressible, that's all the pressure you'd ever see in the scenario shown in the video, and that's assuming it blows that fast out of the hose (which it doesn't). It's different in a flow meter. Especially if it's driven by a positive displacement pump of some type. That fluid has nowhere else to go and the pump doesn't much care if you're at 100kPa or 500. When it's open like that though, and far enough away from the hose's exit, if the inlet pressure is too high it'll just go around it. Hence measuring no more than stagnation pressure. In this case, probably in the few hundred Pa range. Which is why you don't need that much length.
From physics of mechanics someodd 45 years ago… I remember the pressure volume velocity relationship with respect to time and temperature - it would predict a lower pressure (or velocity, or a bit of both) in the narrower pipe. P₁ V₁ ∆T/T₁ == P₂ V₂ ∆T₂ /T₂ We were so amped in those classes, doing the work in our heads half the time. I miss that sort of clarity
Put 50-100 small tubes at the entrance. They guide the air, reduce turbulence, focus into a straight line. Test with different and same tube lengths. Tune for optimal.
The high pressure zone in the wide part of the tube propagates back through your small guidance tubes and the air diverts before those. Don't think of airflow as particles with momentum like water, think in terms of pressure instead, I'm sure it's not perfect but it helps with "paradoxes" like these.
There was no noise the original recording, but the AI which translated the video did not fully understand his explanation. In an spontaneous move it decided "if I do not understand, nobody shall understand".
Just imagine a ton of peas entering the nozzle from the wider opening. At first they all enter fully at no speed change, but then a traffic congestion emerges which moves backwards. If the movement was blocked, the peas inside would be trapped, and a pointy cone would form in front of it, whereas anything else would bypass the cone entirely. However, since there is some flow in the other end, the cone would be shaped somewhat differently, where it wouldn't be pointy but more rounded. Obviously in this mental model as well, the pressure (the collision and contact between the peas) would be the greatest inside the plastic part. And any peas that manage to leave the other end would encounter the peas already in the environment which would help them space apart and accelerate again to ambient speeds.
The pressure differential happens on propellers and wind turbine blades. It's self correcting. Some energy is required as input. But it's goal is usually in another place.
You have a larger opening with energy going in, and a narrower outlet with the same energy going out, the same amount of energy roughly has to go out the narrow end as is coming in the wider opening, so in order for this to work you are multiplying the lower velocity larger opening into a smaller higher velocity exit. The same is true for Volts x Amps = Watts, Hydraulics, F=MA, etc... Energy is preseved no matter what. This is just Bernoulli's principal.
You solved the nature of a fart! That's not a paradox or a mistake my friend. Can you imagine a world without a narrow part? We all must pass through and reason with energy
The paradox is thinking that the higher velocity flow through the narrow tail somehow violates conservation of momentum, but this does not happen. Momentum is conserved. Thank you for the nice video and demonstration.
Simply, does the restriction thus produce a higher velocity from the inlet pressure..but no change in energy. So, no paradox. Reversed, the velocity energy is converted to pressure. Thanks so much for the demo !!
I really love your Vacuum demo.. my only advice is... move the vacuum far far from the mic... like 20' in a different room and get an extension... so it doesn't ruin the audio.
10:00 Answer: The airflow will constrict as it approaches the inlet as the low pressure air behind the bottle tries to reach equilibrium by airflow reversing around the rear rim with simultaneous velocity increase ahead of the inlet. The conical front taper will increase air pressure near the inlet as part of the inlet stream constriction and acceleration effect. Essentially an invisible front half of a venturi forms ahead of the bottle.
Nice way to think about it. I knew as much goes in, comes out, volume flow is equal, so the rate is proportional to area of the points in the flow. Works easier on liquids, a pressure-centric view is more in line with the aero guys haha.
Is this video AI generated? Very odd body and mouth movements, often very visible. Okay, I think I got it: There is a Russian original, and they use AI for translation, AI for new English voice, and AI for replacing the mouth movements! I think viewers should be informed first, as every time they do not see reality, everywhere.
@@akh345 ? your comment makes no sense. This is a video that has been altered. The original video is in Russian, and I explained how it was modified. Perhaps your comment is AI then :)
Nice video and presentation. By page 5:00~ is an assumption that a nominal flow passing through a cross section smaller than the engine diverges towards the inlet. It is also true that air flow passing a through a criss section multiple times larger than the engine converges towards the inlet. We also saw a simplified experiment showing pressure distribution along the path one end to another. It seems we have mixed messages and questions. The exhaust after the vacuum cleaner has top speed and least pressure relative to the ambient and its speed is being drag down by friction imposed by the funnel inside surface, stagnating with pressure rise before leaving the funnel. The air stream increases again by the end of the funnel. We just complete a “passive” wind tunnel experiment is irrelevant to what we advocate “air flow in and out of a turbine engine.
I don't see a paradox. The input of energy is provided by the airplane. The pressure inside the wide part of the funnel increases because the air is approaching a flow restriction. There is no reason to invoke expansion of the air. As a result of the increased pressure in the wide section, the speed of the air increases as it is forced into the narrow section. Once in the narrow part of the funnel, the pressure is high but instantly returns to atmospheric, not below atmospheric, as it exits the funnel because it opens to the atmosphere which has a volume infinitely bigger than inside the narrow part of the funnel (P1V1 = P2V2). Conclusion, the energy provided by the plane in order to accelerate the air in the narrow section is not given back to the airplane, which results in slowing down the plane, although the reduced speed is so minuscule that we cannot even measure it.
14 дней назад
This explains it best. That was what I was thinking.
@@mosab643 The pressure is highest at the entrance of the narrow part, as you saw in the video experiment. As the air speed increases in the narrow tube, the pressure decreases (Bernouilli principle) and back to atmospheric pressure as it exits the tube. It cannot drop below atmospheric pressure, otherwise the air would flow back from the outside into the narrow tube. Actually, this brings up an interesting thought: maybe the refined theory seen in the video is correct and indeed there is a negative pressure, but the atmosphere fills it back instantly from the exit of the funnel, and an equilibrium quickly takes place so that the pressure is equal to atmospheric pressure. This is something to consider. Sorry, I'm not a fluid engineer, just a chemist with a wide imagination.
@@pjdruz5636 No, that actually makes a lot of sense. However, the pressure can theoretically be less than the atmospheric pressure in the narrow part of the tube depending on which type of pressure you are talking about; as there are two types of pressures in a flowing fluid - static pressure and dynamic pressure. Static pressure can be seen as the pressure the fluid exerts due to its internal energy, and its affects are measured parallel to the direction of its stream. Where as, the dynamic pressure is the pressure that the fluid exerts due to its motion, in the direction perpendicular to the direction of its stream. So, the static pressure - the pressure being exerted on the walls of the tubes - can indeed be less than atmospheric pressure without the outside air having to flow back into the tube.
The pressure gradients are analogous to those of a wing's airfoil. High pressure at the leading edge up to the thickest part where the flow is slowed, low pressure across the retreating surface behind the thickest point, and atmospheric once again beyond the trailing edge.
I like the theories and the demonstration, but what hasn’t been discussed here is what is happening to the external pressures as the air moves around the outside of these conical structures, it creates a low pressure zone behind the outer cone before the air exits. I don’t agree that this would create a small or unmeasurable drag if such a conical device was attached to an aircraft though, because I feel it would act like a donut shaped sail overall and create quite a bit of drag as it compresses the inner chamber while decompressing the external atmosphere behind the cone before the exit and would also make the aircraft much less aerodynamic with such a structure attached. I imagine reversing the jet type cone would cause higher external pressures on the outside rear of the nozzle and hence a decompressing effect for air exiting the larger diameter of the jet type nozzle. JMO.
@ Any air that is forced through such a conical shape or device would be considered compressed if the pressure is raised as was shown by his metering device.
@@evil17 I am trying to differentiate between under pressure versus compressed as in a volume change. If you think of water flow you don’t think of a volume change, but you still have the pressure changes due to flow through the nozzle. Was the water compressed, or was there a pressure change? Now extend that to the airflow.
This presenter reminds me of Nikolai Kuznetsov, the Soviet-era chief designer of OKB 276, the development center that designed many of the highest-performance jet engines of the cold war, and also the NK-33 rocket engine (still in use today as the Aerojet AJ-27). When built, the NK-33 was the most thermodynamically efficient rocket engine in the world, a title it held for over half a century until the Space X Merlin.
@@gurglejug627 _"and yet you haven't managed to define or elaborate on a single one."_ Because people like you that couldn't possibly understand the basics, would be like talking with a wall explaining the complex that you are missing.
Oh, please, do elaborate. I mean he's not talking quantum physics here. And barely brushes on particle physics. It's simply fluid dynamics in relation to atmospheric pressure throughout a constricted path. Granted, air/fluid velocity should have been discussed in more detail but as an overview I think it was rather well done
@@villainbydesign _"Oh, please, do elaborate."_ Oh... I did... I explained in detail to They/Them gurglejug62d7, just under They/Thems comment. In about 200 to 300 words. It hurt their feelings so much that they/them reported it to YT as "Hate" speech and it was deleted. Please explain to us all what you are not missing, and I'll go into detail what you are missing. That is after I have your comment deleted by YT as "Hate" speech... What? It is only okay for delusional people like you to have comments that hurt your feelings deleted as "Hate" speech??? Yea, we know none of you are for freedom of speech... Well, you are... Just freedom of speech that doesn't hurt your feelings.
Why is there a paradox? The increase in the flow rate should increase the backpressure to resist it due to the restriction. Eventually, the a rise in backpressure should result in a negative pressure within the restriction. When you add a recovering combustion cycle between the pressure zones, this becomes a completely different fluid cycle, and the restriction induces a region of focused high pressure at its exit.
Sir: I watched thinking "What is the big deal, he's created an incomplete venturi." In my dad's first airplane, we would not have gyros without a vacuum. The Venturi engages Bernoulli's Theory. The Venturi converted some of the forward motion energy into outflow from a system of tubing connected attitude and direction gyro instruments.
Do you think there's something counter-intuitive in the venturi tube or Bernouilli's theorem? Pressure increases when speed decreases? HVAC field tech manager POV.... Many people have a hard time wrapping their heads around that one.
@@aeomaster32 What do you mean? I usually measure air velocity in a duct with a pitot-tube connected to a digital manometer. The volume and velocity of the flow can be calculated from the difference between static and dynamic pressures when the duct diameter is known. Static and dynamic/impact pressures are equal when there is no flow. That's why you can't tell whether air is moving or not, not to mention calculating it's velocity, from static measurements only. You need at least a pressure differential across a quantified restriction in the duct. Static pressure is the same in all directions and equals dynamic.pressure only when the medium is standing.still.
@ I was not challenging you, but considering what happens at the choke point of a venturi. At its narrowest point the airflow speeds up (increase in dynamic pressure) and the static pressure simultaneously drops at that point. The sum of the lower static and higher dynamic pressure should be the same as free atmospheric pressure. Airflow over the top surface of a curved wing section speeds up (dynamic pressure) over the curve (like a veturi) and there is a drop in static pressure there causing the higher atmospheric pressure under the wing to lift it up.
@ A wing doesn't generate lift by itself and a venturi doesn't generate more flow than what's put in. Small pockets of minute low pressure at the outlet don't add to the system or create thrust although the air molecules are slightly accelerated. The relationship between air volume and the required static pressure and motor power is staggering : to increase air volume 2 times pressure needs to increase 4 times and motor power 6 times. A venturi is a deliberate restriction of a certain known magnitude with known coefficients that consumes the energy of optimal near-laminar flow. He does mention surface friction as a factor but doesn't address more important ones, e.g. the way air behaves when it's forced to compress and converge. Air molecules that enter the funnel are being deflected inwards towards the same axis and the steeper the angle of the taper gets the more they interfere with the main axis of flow and each other, create turbulance, and some are reflected backward so the flow is partly reversed. The turbulent air might give you high pressure readings because there's so many air molecules pushed together and in different directions. Both the volume and velocity of the air flow are greatly reduced in the funnel and what is eventually slightly accelerated by the low pressure zone at the outlet is minimal in volume, energy, thrust, how ever you want see it. High speed doesn't equal high power or addition of energy. There can be no equation when the amount of energy put in or coming out of the system is not known.
People are complaining, but are not realizing what a wonder they are seeing. This is a russian speaker, who has had their language translated, with their lips synced, in THEIR natural voice! This has effectively eliminated the language barrier!
This is just INSANE. If someone is complaining about this they are NOT understanding how useful this will be in the future! Right now actually. This will eliminate the advantage english speaking nations have during negotiations, entertainment, and so on.
Great video, just a little short but you cant learn everything about in just a single one. I expect further videos on fluid dynamics Already suscribed!!
It seems obvious to me that when the air enters the wide gap, it meets resistance and seeks the easiest way out. This creates turbulance ad air seeks to back out while crashing into incoming air. It would seem intuitive that the increased pressure would force air through the narrow side, but in my mind, the turbulance increases as you get further along the narrow passage, thus the drop in pressure. The turbulace and the higher pressure would seem to create an invisible bulge in front of the wide end, diverting incoming air to the sides of the tube. Spill over turbulance, being driven back over the outer wall of the tube accounts for the lower pressure there. What I would be interested in seeing is if there would be a pocket of lower air pressure out in front of the wide end, out beyond where the higher pressure from the tube could be sustained. It wouldn't surprise me if the diversion of the incoming air to the sides creates a small pocket of low pressure somewhere out in the open air. As for turning the tube the other way. I think the key will be the air flowing along the outside. Whether it is turbulant or slightly higher pressure, I think the big effect will be when it blows past the edge of the wide end. This will naturally drag air out from the tube, creating a vaccum, I think. The low pressure though may cause a feedback pulse. As the pressure drops, it will cause air to be pulled in from the narrow end quicker. As this happens, it will reduce the pressure in front ot the narrow end, which will take pressure from the air going along the outside, which will reduce the vaccum effect in the wide end. Thus the narrow end pressure will rise impeding air tlow, imcreasing pressure in front, increasing pressure along the outside. This returns us to imcreasing the vacuum in the wide end again. It wouldn't surprise me if this generates a mild whomp whomp sound as the air flows and the pressures cycle around the tube. Tbis is of course wild speculation, so it is likely to be all wrong.
Eh... kind of... to a point... if your geometry is perfect... 😅 Most of the time viscosity has something to say about it and you very quickly enter the chaotic realm of turbulence modelling. Flow separation is a major headache.
- This paradox is the problem with most attempts to duct wind turbines - Downstream flow is key not upstream, in passive systems. The presumed ram effect tends to cause freestream air to flow around the positive pressure gradient...
First, the work done on the air by the larger portion of the tube is equal to the output of smaller exit of the tube. The liquid\gas can accellerate in the smaller exit, but it is not creating any work. Rather, the pressure must equalize before and after the "engine" and since there is no additional work being done on the air in the pressure chamber, there is no net force of accelleration, only drag due to turbulence. If the cone is reversed, the pressure will increase at the opening of the smaller tube, then drop below atmospheric pressure inside the widening chamber. A great deal of turbulence is created at the rear of the reversed or widening tube. In this case, the work done on the outside of the engine reduces pressure, and relative pressure inside the engine is even lower or equal to the airfoil effect on the widening portion of the tube--as it straitens out.
The energy to accelerate the air comes from its internal energy. That's why the pressure decreases. Part of the Brownian motion of the air molecules becomes coherent motion.
In this video, the velocity of the air inside the outlet tube is definitely greater than the velocity inside the inlet tube. There is no doubt about it. Because the pressure inside the inlet tube will be higher than atmospheric pressure. If you blow the inlet of this tube with a fan like in the video. If we put this tube in a wind tunnel, the inlet pressure should also be higher than the outlet pressure. Will there be a reaction force at the outlet of the tube? it will be. But this reaction force is not acting on the tube, but on the air. So it cannot become the engine of an airplane.
You know narrowing conical shapes are used in supersonic jet engines to slow down the incoming air? An increase in pressure, i.e. narrowing of the tube, slows the air down so it's suitable for the rotor. The air speeds up when pressure eventually drops at the outlet.
@@enbinzheng-line Yes. "Bernoulli's principle states that an increase in the speed of a parcel of fluid occurs simultaneously with a decrease in ... pressure." Notice that it doesn't say that lowering the pressure at source of the flow will always increase the speed of the medium downstream. Additionally all this applies to static pressure which he is trying to measure here. It's quite logical when you get your head around it. Try this: a high speed flow of air in a duct meets a restriction and is forced in to a narrower duct. Of course the flow will slow down bc all that air won't fit in as easily. Simultaniously the pressure it exerts on the walls of the duct is increased bc the same mass has to fit in to a smaller space. And vice versa, when the duct opens up to a larger diameter the air speeds up while the presuure it exerts on the walls decreases.
@@Kansika What you said is incorrect. The fluid is continuous. Assuming the fluid is incompressible, the volumetric flow rate inside the tube is constant, so the fluid velocity at the inlet of the converging tube must be lower than that at the outlet.
@ There's no incompressible variables here. What he theorizes, models and measures don't add up. Why not set up a venturi tube yourself and test if Bernoulli was wrong? First of all the CAD model shows a cone with an even diameter extension nearly as long as the cone. The model he built only has a cone and an outlet. Not the same thing. A taper or a restriction always causes turbulance that takes a while to settle. Secondly he's holding the end of the probe tube away from the direction of flow. Air flowing over tuhe tube creates an eddy flow at the tip creating negative pressure zones. The least he could do would be to take more readings with the nozzle facing the flow. That would be the dynamic pressure and subtracted from the static pressure it might give some hints about air velocity. But like I said he's not measuring static or dynamic presuure here. I use a pitot-tube with a digital manometer to test ultra-sonic air flow sensors at work. Turbulent air is very hard to measure. All and all, air speed is not what he measured here.
This video reminds me a little bit of another video on optimal feeding of ball bearings through a hopper. Although the principles are not exactly the same, I can see where the taper of the funnel has importance.
To add a spin of sorts... pressure converts to flow and the reverse. We need to measure both to get a picture. If the fluid slows the pressure will rise. If the fluid increases speed in the narrowing part... it should have a lower pressure.
At first thought the conundrum is solved by the additional thrust of the plane we are riding on required to make up for the overall drag of the device.
Without any study in physics it seems to me the funnel restricts the air flow if placed in either direction, except for the line of travel directly straight through the small opening of the funnel. When the large opening of funnel faces the oncoming flow of air it allows more mass of air in and creates higher pressure and air velocity out the small opening of funnel. If funnel was in opposite direction, the ambient air would be diverted around the outside of the funnel and no higher pressure would result.
Video is excellent and educational (for younger especially). But, from the title "paradox", = it is not paradox, paradox is something which happens very rare or out of something you see every time of often or out of all the time. (but to rise interest in physics, it is good) It is normal matter density to make balance, (it is with harder matter example: if you remove 2/3-rds from cup with water, normally 1/3-rd stays. Even it looks funny to many, because is normal) when same air in one part of pipe becomes more dense - just near it has to become bellow normal density - because it has to take it from somewhere. So, paradox would be: if everywhere becomes more density and rest to be normal density, that would be: "from where more matter suddenly".
The gentleman first described this as a free energy device. In other words, a perpetual motion machine. That is simply not possible. The air exiting the narrowed tube does produce a forward force, but the drag created by the constriction is greater.
This was very interesting for me as I had a practical example, and this explains why it failed. I had assumed it was drag. As an experiment I purchased a drogue or sea anchor, a large canvas funnel 60 cm wide end, 6 cm narrow end. I expected that when set-up in a slow moving creek, I would get enough exit velocity (minus drag) to run a river gold sluice or even a high-banker. It made for a good facebook joke though: 'I am now the proud owner of a drogue (image) They told me I ought'a buy a boat first, but I like to do things differently!'
It is better to refer to pressure by its components. Total pressure is constant unless energy is added but the static and dynamic pressure can be exchanged without adding energy. When you slow the air it's static pressure goes up but it's dynamic pressure goes down and vice versa when you speed it up but the sum of the two, which is the total pressure, is always constant. This remains true until the air becomes considered compressible usually above Mach 0.5 and higher.
When the cone is flipped my guess is there would be increased atmospheres at the entrance, as the laminer flow around the exit essentially grabs hold of what's coming through the cone.
At a guess, reversing the air flow direction would be, to first order, like running the original in time reverse so the pressures would be identically distributed. Frictional forces aren't time reversible so there'd be some differences. I expect the dynamical explanation would feel very different though from for the original.
I see an error in your test where you measured air pressure over/below atmospheric. Your exit did not have a tube like your model did, that is why you never saw the negative pressure your computer model predicted. Bernoulli’s theory says if you restrict the flow of a fluid, velocity increases and pressure falls. Since there was no long tube in your exit, the restriction disappeared too soon for you to measure the reduced pressure caused by the increased flow inside the restriction. You actually did measure a bit of negative pressure but the tube was not long enough to show it definitively. Try it, you will see I’m correct. As a measurement technician I studied this effect in school as we use this same effect in industry to measure flow inside pipelines. We introduce a precision restriction inside the pipe and measure the pressure upstream and downstream and can accurately measure volumetric flow.
When fluid flow exits a pipe at subsonic speed into a large reservoir, it forms a jet and the static pressure at the exit plane inside the jet MUST be equal to the static pressure outside the jet, which is the pressure in the reservoir. This can be proven by the following reasoning. Let's keep it simple by assuming inviscid incompressible flow; i.e., no friction with the Mach number squared much less than unity. First, let's assume the exit pressure in the jet is above the reservoir pressure. That means the jet must expand as it enters the reservoir, which in turn means the flow area of the jet increases along the jet. If the area increases, the continuity equation requires that the flow velocity must decrease, and the incompressible Bernoulli equation requires that the pressure in the jet increases. Using the same reasoning for points further downstream of the jet, we realize that the pressure in the jet will always increase and never reach the reservoir pressure. This is impossible. If we assume the exit pressure in the jet is lower than the reservoir pressure, the flow area must decrease, resulting in an increase in velocity and a decrease in jet pressure, meaning that the jet pressure would always decrease and never reach the reservoir pressure. This is also impossible. The only physical result is that the exit jet pressure must be equal to the reservoir pressure. Thus, the pressure at the entrance to the larger diameter end is a little higher than the reservoir pressure because some of the kinetic energy (0.5 Rho V^2)of the free stream flow is converted to potential energy, or pressure, because the tube is an obstruction. I thus conclude that the figure showing the magnetic flux lines is incorrect. When the tube is turned around, we can reason that the exit pressure in the jet leaving the larger diameter end must again, as before, be equal to the reservoir static pressure. That exit pressure must be larger than the pressure at the entrance to the smaller diameter end, because the tube is acting as a diffuser - fluid flow with increasing diameter, using the same equations of conservation of mass and Bernoulli (conservation of mechanical energy). This latter fact leads us to conclude that the entrance pressure at the smaller end must be a little lower than the reservoir pressure. Thanks for the interesting discussion.
I am amazed that i found this video purely by accident. I have maybe a kind of inverse paradox that might be very similar. Can you explore this for me? I had a need for a very small but strong vacuum cleaning device. I put an inverse funnel shaped attachment on a very powerful shop-vac vacuum cleaner, and had the cleaning tube side with a very small maybe 4mm opening (it was some narrow plastic tubing). In my mind I was expecting the tube would suck air very strongly, kind of like the dentist uses. The paradox was, it felt very weak, that powerful shop-vac motor was straining but could not provide the results I wanted.
If the pressure in the cylinder were below atmospheric, then the higher pressure of the atmosphere aft of the cylinder would cause air to enter from the back to equalise the pressure. I'm guessing there would be some flow separation of the front to rear airflow towards the end of the cylinder's inner surface.
The "paradox" is never resolved. Of course there never was one to begin with, because comparing the velocity of the air doesn't cut it. The comparison should incorporate flux as well. On another note, the reduced pressure in the narrow tube is to be expected as this is basically a venturi tube.
I missed some of the vital information because of the bloody vacuum cleaner. However my prediction is that in the reversed pipe an area of high pressure will form as the air flow slows down. 😊
You forgot that air have no laminate flow and also temperature hot spots put also into account the angle of the reverse flow perpendicular to the angle of attack inside and outside the jet tube
Further the inlet conform whatever form have to have a maximum inlet degree of10 ,all in all there will be no gain in flow unless creating an artificial low pressure at the end
7:00 A better explanation of what the colors signify is definitely needed at his point. The viewer is forced to infer what colors are higher and what colors are lower. My question is where in the airstream did you take your pressure measurements, it was difficult to see. Were they in the center, off center, or near the wall? I would like to see some lateral pressure measurements from wall to wall at several distances in the cone.
I'm thinking out loud, no shade on you at all. If its sitting on top of a plane, there IS energy input with it sitting on a plane. the moving plane is giving it energy. wouldn't it create a vacuum at the inside of the taper? Now that you showed me the vismach i understand the airflow. VISMACH as in linuxcnc vismach? where are you getting the vismach program from? As far as it being an "engine", IMO, the losses due to friction would make it essentially useless as an engine. I'm trying to think of some proctical use cases........Great experiment. Guess what? You get a like, comment, and subscribe.
6:41: How come there is a blue patch in the further most right of the tube where distance between two adjacent streamlines is decreasing? I would expect blue to the right of central stream, where the meter showed it. It seems another virtual funnel will be opening up to the right of exit.
Cool video for reasoning dynamics, but there is nothing close to a paradox. It's a paradox if you don't calculate either the energy in the wind from the model, or the torque from the plane in the hypothetical.
You could with the same success demonstrate that peas dropped in the funnel fly out faster on a bottom than enter it at the top and argue that this should mean that the funnel might fly upwards due to pea jet stream. If you reversed the funnel in the air, I believe it would have normal pressure in the narrow part and lower in the wider.
If someone is talking about a paradox, it simply means they dont understand. Not only do they not understand the subject matter, they dont understand what a paradox is. This is not a paradox. Also, "Neural translated" is not a sufficient declaration that the video material is produced using AI.
I'm not really sure it's an actual paradox as much as a counter-intuitive phenomenon. When flowing air is compressed in to a narrow channel it's pressure increases and it's speed decreases. The highest pressure measurements mean the slowest air speeds. When the pressure drops again the air speed increases. Add a combustion element to that and you have a jet engine. In supersonic jet engines the intake nozzle and cone work to slow down the incoming air to sub-sonic so the engine can handle it. The decrease in pressure amplified by the combustion gases at the outlet nozzle give the air it's super-sonic speed.
Imagine two pipes of different diameters connected by a smooth adapter. Now let us place this structure in the air flow with its wide end forward or, what is the same, move it relative to the stationary air. The flow enters the wide part of the tube, then passes into the narrow part, and at the same time, obviously, increases its velocity. Have we really got an air gas pedal, a kind of jet engine that runs without any fuel?! Something's not right here. A metaphysician like Newton will immediately say that the Creator of all things so arranged the universe that man could not get something for nothing, and such an engine is a priori impossible. And a physicist (like Newton) should find an error in this very plausible reasoning and understand in what exactly we deceive ourselves. Let's follow the air pressure along the axis of the pipe. Behind, at the exit from the narrow pipe, the pressure is atmospheric, as well as inside it: the air flies there by inertia. But in the adapter and in front of it, the pressure must be greater than atmospheric to drive the air into the narrow pipe and increase its speed. But before the wide pipe the pressure is again atmospheric, so at the entrance to the pipe in the area where the pressure increases, the air flow slows down and expands. So far ahead of the pipe, the cross-sectional area of the flow that will then enter the pipe is smaller than the cross-sectional area of the wide pipe and probably equal to the cross-sectional area of the narrow pipe. Then there is no acceleration of the air - with what speed the air moved far ahead of the wide pipe, with the same speed it flows out of the narrow pipe from behind. Here, as in other cases where we encounter seeming paradoxes, it is important to draw the lines of current correctly. For example, the wing of an airplane not only deflects the airflow downward behind the trailing edge, but also causes it to run into the leading edge from bottom to top, rather than horizontally. Or else: water moves much faster in the inside of a pipe bend than on the outside. And as in many videos devoted to hydrodynamics, we simulate the flow of our “engine” using the Vizimag program, because the mathematical equations describing the motion of an ideal fluid and a magnetic field are exactly the same.
Seems odd to explain pressure without bringing up the inverse relationship of volume. What about the effect of heat on the pressures of a jet engine? Finally, what about what a cross-sectional view of the tapered pipe showing the different rates of flow? Is the rate of flow universal across and throughout the pipe? In an ICE with a turbo or supercharger where the flow is externally induced the effect is call boost.
You will have an increase in velocity in the tube but no thrust....as it is just a tapered tube...increase the velocity of the tube to mack 2 add some atom Atomized fuel and you have a scram jet.
Too many people complaining. This is great. The internet was supposed to be used as an educational tool and I applaud your contribution to the effort. Thanks for this!
My prediction for the pipe in reverse is that a low pressure zone will form at the center of the pipe as the air expands with the taper.
AI translation and video matching. What a time we live in. Good video.
I would not mind just using the good old reliable subtitles or narrator. AI soles an issue that was not an issue.
@@KlausNietzsche And better yet, we should all be learning each others languages. It is 100x easier to learn a language today than 30 years ago and 1000 easier than 100 years ago. There is a lot lost in translation.
We all should be speaking 5-10 languages naturally by the time we are 20. Well, if we were not ruled by criminals, morons, and psychopaths.
@@KlausNietzsche it is an issue though, those are barriers to the audience. We should be lowering barriers to knowledge
@@Grunttamer a narrator is not a barier....
@ a human narrator that speaks whichever language you desire is pretty expensive. Expense is the barrier
so many criticisms and yet no competing videos. For me, this was an excellent video. An excellent visual representation of P1V1=P2V2
Agree. Childish.
Absolutely when there critiquing the person they're not paying attention to the lesson.
I'm a video competing, cash me outside, how bout that?
@@forrestparsons2378some people are too funny to be taken seriously and them digging their heals about it, makes them appear more helpless and less help able, so you outta time sucka!
@@forrestparsons2378 Что такое ислам?
🔴 Ислам - это не просто еще одна религия
🔵 Это же послание проповедовали Моисей, Иисус и Авраам.
🔴 Ислам буквально означает «покорность Богу».
🔵 и учит нас иметь прямые отношения с Богом.
🔴 Это напоминает нам, что с тех пор, как Бог создал нас, никому нельзя поклоняться, кроме одного Бога.
🔵 Он также учит, что Бог не похож на человека или что-либо, что мы можем вообразить.
🔴 Концепция Бога кратко изложена в Коране как:
{ Скажи: «Он - Аллах Единый,. Аллах Самодостаточный. Он не родил и не был рожден,. и нет никого равного Ему».}
(Коран, 112:1-4)
🔵 Стать мусульманином - это не повернуться спиной к Иисусу.
🔴 Скорее, это возвращение к изначальным учениям Иисуса и повиновение ему...
Bro has some shape shifting going 🙀 on. Had to rewind a few times 🤯 to look again!
Yea, it's here 02:09. That said, he's gonna be freaked out this is all decades-old fundamental physics in regard to a parachute design with a central vent hole. Patent Number: 5,360,187 found at nasa.gov He reminds me of my uncle after he's done a few shots of Jack and smoked a bowl.
If this video or channel never used AI to translate the audio AND visuals of this original video to an English video, I probably never would have seen this and possibly never learned this. Politics aside, AI directly allowed me to learn this. That's crazy, and AI is the future. Great video!
It's a paradox that anyone can wear a shirt like that and act normal
Asperger's meets AI. A marriage made in silicon! Just pulling your leg. I found this presentation very interesting and a most excellent use of AI translation. Anything that brings people together and promotes the sharing of knowledge gets my approval. I signed up immediately.
ever considered a career on stage? So funny I can't stop. Honest.
@@gurglejug627 I'm laughing too.
The only things I've ever seen that were funnier are your ego and your face.
@@TimeSurfer206 I can't wait until you can think of anything in any way funny, interesting or intelligent to add... everyone has a first time- go on, try...
@ And you still haven't said anything that proves me wrong, little NPC.
@ you haven't mentioned who you're addressing, Mr Charisma. Now run along before you get even more... yawn...
The nice thing about measuring relative pressures is that it's extremely easy to set up a basic yet very accurate differential manometer.
All you need is a clear tube, some watter with food dye in it (so you can see it easily) and a board to mount the tube in a U shape. Then you fill it about halfway with the dyed water and connect both ends to the pressure locations you want to compare.
Super eaay to build, very visual, very intuitive.
Add some line markings and you have a proper instrument 😁
Every 27.68” of height differential equals 1 psi if you are using pure water. (Dye could change this)
@rickschlosser6793 Usually you're dealing with a few Pa at most, especially when you're playing with vacuum cleaner wind tunnels. So you don't need much length at all 😉
@ Our flow meters were ranged 0-100kPa, and upset conditions could pin the meter on the high side.
If you call 100kPa just a ‘few’ kPa, then fine.
That type of meter is even more.accurate if either tube is at a lower angle.
What you cant't directly deduce from that is air flow.
You need either static vs dynamic pressure or.air velocity for that.
His probe is opposite thae air flow. It's not a true static pressure reading bc Eddy currents, etc, and the deeper.he goes the more the device alters the flow.
Good points, though.
@@rickschlosser6793 100kPa isn't much in the grand scheme of things, but I was talking specifically for this demo. This is ram air out of a vacuum cleaner, 100kPa is overkill.
For reference, stagnation pressure at 100m/s is just over 6kPa. Outside of going compressible, that's all the pressure you'd ever see in the scenario shown in the video, and that's assuming it blows that fast out of the hose (which it doesn't).
It's different in a flow meter. Especially if it's driven by a positive displacement pump of some type. That fluid has nowhere else to go and the pump doesn't much care if you're at 100kPa or 500.
When it's open like that though, and far enough away from the hose's exit, if the inlet pressure is too high it'll just go around it. Hence measuring no more than stagnation pressure. In this case, probably in the few hundred Pa range. Which is why you don't need that much length.
From physics of mechanics someodd 45 years ago… I remember the pressure volume velocity relationship with respect to time and temperature - it would predict a lower pressure (or velocity, or a bit of both) in the narrower pipe. P₁ V₁ ∆T/T₁ == P₂ V₂ ∆T₂ /T₂ We were so amped in those classes, doing the work in our heads half the time. I miss that sort of clarity
Nostalgia is a pleasant feeling ))
A paradox is better than one
I try to have 3 dox on hand, for emergencies.
Hahahaha
What about a paradix?
@ Donald and Elon
Actual great. "Pressure line and magnetic line are identical " 😮🤯
Sorry, the dialogue during the part where the air is blowing through the tube is hilarious
LOL!
Put 50-100 small tubes at the entrance. They guide the air, reduce turbulence, focus into a straight line. Test with different and same tube lengths. Tune for optimal.
The high pressure zone in the wide part of the tube propagates back through your small guidance tubes and the air diverts before those. Don't think of airflow as particles with momentum like water, think in terms of pressure instead, I'm sure it's not perfect but it helps with "paradoxes" like these.
Known as a gas lens. Works great for creating a laminar cover gas flow for welding. I've made a number of them for laser welding applications.
You can get longer extension tubes for your vacuum so you can place the vacuum in another room and not have to deal with the noise.
There was no noise the original recording, but the AI which translated the video did not fully understand his explanation. In an spontaneous move it decided "if I do not understand, nobody shall understand".
Just imagine a ton of peas entering the nozzle from the wider opening. At first they all enter fully at no speed change, but then a traffic congestion emerges which moves backwards. If the movement was blocked, the peas inside would be trapped, and a pointy cone would form in front of it, whereas anything else would bypass the cone entirely. However, since there is some flow in the other end, the cone would be shaped somewhat differently, where it wouldn't be pointy but more rounded.
Obviously in this mental model as well, the pressure (the collision and contact between the peas) would be the greatest inside the plastic part. And any peas that manage to leave the other end would encounter the peas already in the environment which would help them space apart and accelerate again to ambient speeds.
Great
"The pressure would be greatest inside the plastic part." 😶
_Every part of the apparatus is plastic._
@@assininecomment1630 I see no confusion then....
The pressure differential happens on propellers and wind turbine blades. It's self correcting. Some energy is required as input. But it's goal is usually in another place.
You have a larger opening with energy going in, and a narrower outlet with the same energy going out, the same amount of energy roughly has to go out the narrow end as is coming in the wider opening, so in order for this to work you are multiplying the lower velocity larger opening into a smaller higher velocity exit. The same is true for Volts x Amps = Watts, Hydraulics, F=MA, etc... Energy is preseved no matter what. This is just Bernoulli's principal.
You solved the nature of a fart! That's not a paradox or a mistake my friend. Can you imagine a world without a narrow part? We all must pass through and reason with energy
Thank you for this good video.
Anyway, with my built-in speakers in the monitor it is like
„ .... the pressure is zero .... “
The paradox is thinking that the higher velocity flow through the narrow tail somehow violates conservation of momentum, but this does not happen. Momentum is conserved. Thank you for the nice video and demonstration.
Simply, does the restriction thus produce a higher velocity from the inlet pressure..but no change in energy. So, no paradox. Reversed, the velocity energy is converted to pressure. Thanks so much for the demo !!
Kinetic energy (rate of flow of air or air speed) is converted into potential energy (increase in pressure)
I really love your Vacuum demo.. my only advice is... move the vacuum far far from the mic... like 20' in a different room and get an extension... so it doesn't ruin the audio.
10:00 Answer: The airflow will constrict as it approaches the inlet as the low pressure air behind the bottle tries to reach equilibrium by airflow reversing around the rear rim with simultaneous velocity increase ahead of the inlet. The conical front taper will increase air pressure near the inlet as part of the inlet stream constriction and acceleration effect. Essentially an invisible front half of a venturi forms ahead of the bottle.
Nice way to think about it. I knew as much goes in, comes out, volume flow is equal, so the rate is proportional to area of the points in the flow. Works easier on liquids, a pressure-centric view is more in line with the aero guys haha.
A paradox is twice as much as a single dox.
Twice as much as a single dox is a bidox, also called a didox or duodox. A paradox is the stuff beside or around a dox.
Is this video AI generated? Very odd body and mouth movements, often very visible.
Okay, I think I got it: There is a Russian original, and they use AI for translation, AI for new English voice, and AI for replacing the mouth movements!
I think viewers should be informed first, as every time they do not see reality, everywhere.
I was literally questioning my judging ability.
Is this comment AI generated? I mean a human would easily recognize that they are just watching an elderly gentleman talking about physics
@@akh345 ? your comment makes no sense. This is a video that has been altered. The original video is in Russian, and I explained how it was modified. Perhaps your comment is AI then :)
Am i Aİ gene .. aahh.. whatever..
Only AI exists, nothing else:) And I am the author of this video (in Russian).
Nice video and presentation.
By page 5:00~ is an assumption that a nominal flow passing through a cross section smaller than the engine diverges towards the inlet.
It is also true that air flow passing a through a criss section multiple times larger than the engine converges towards the inlet.
We also saw a simplified experiment showing pressure distribution along the path one end to another.
It seems we have mixed messages and questions. The exhaust after the vacuum cleaner has top speed and least pressure relative to the ambient and its speed is being drag down by friction imposed by the funnel inside surface, stagnating with pressure rise before leaving the funnel. The air stream increases again by the end of the funnel. We just complete a “passive” wind tunnel experiment is irrelevant to what we advocate “air flow in and out of a turbine engine.
The vacuum killed the dialogue. Not a paradox.
I don't see a paradox. The input of energy is provided by the airplane. The pressure inside the wide part of the funnel increases because the air is approaching a flow restriction. There is no reason to invoke expansion of the air. As a result of the increased pressure in the wide section, the speed of the air increases as it is forced into the narrow section. Once in the narrow part of the funnel, the pressure is high but instantly returns to atmospheric, not below atmospheric, as it exits the funnel because it opens to the atmosphere which has a volume infinitely bigger than inside the narrow part of the funnel (P1V1 = P2V2). Conclusion, the energy provided by the plane in order to accelerate the air in the narrow section is not given back to the airplane, which results in slowing down the plane, although the reduced speed is so minuscule that we cannot even measure it.
This explains it best. That was what I was thinking.
He is using the word "paradox" loosely; sort of like when the word "theory" in common usage is different from a "scientific theory."
Why did you say "Once in the narrow part of the funnel, the pressure is high"? You do agree that it should be at its lowest if the flow is laminar?
@@mosab643 The pressure is highest at the entrance of the narrow part, as you saw in the video experiment. As the air speed increases in the narrow tube, the pressure decreases (Bernouilli principle) and back to atmospheric pressure as it exits the tube. It cannot drop below atmospheric pressure, otherwise the air would flow back from the outside into the narrow tube. Actually, this brings up an interesting thought: maybe the refined theory seen in the video is correct and indeed there is a negative pressure, but the atmosphere fills it back instantly from the exit of the funnel, and an equilibrium quickly takes place so that the pressure is equal to atmospheric pressure. This is something to consider. Sorry, I'm not a fluid engineer, just a chemist with a wide imagination.
@@pjdruz5636 No, that actually makes a lot of sense.
However, the pressure can theoretically be less than the atmospheric pressure in the narrow part of the tube depending on which type of pressure you are talking about; as there are two types of pressures in a flowing fluid - static pressure and dynamic pressure. Static pressure can be seen as the pressure the fluid exerts due to its internal energy, and its affects are measured parallel to the direction of its stream. Where as, the dynamic pressure is the pressure that the fluid exerts due to its motion, in the direction perpendicular to the direction of its stream.
So, the static pressure - the pressure being exerted on the walls of the tubes - can indeed be less than atmospheric pressure without the outside air having to flow back into the tube.
The pressure gradients are analogous to those of a wing's airfoil. High pressure at the leading edge up to the thickest part where the flow is slowed, low pressure across the retreating surface behind the thickest point, and atmospheric once again beyond the trailing edge.
I like the theories and the demonstration, but what hasn’t been discussed here is what is happening to the external pressures as the air moves around the outside of these conical structures, it creates a low pressure zone behind the outer cone before the air exits.
I don’t agree that this would create a small or unmeasurable drag if such a conical device was attached to an aircraft though, because I feel it would act like a donut shaped sail overall and create quite a bit of drag as it compresses the inner chamber while decompressing the external atmosphere behind the cone before the exit and would also make the aircraft much less aerodynamic with such a structure attached.
I imagine reversing the jet type cone would cause higher external pressures on the outside rear of the nozzle and hence a decompressing effect for air exiting the larger diameter of the jet type nozzle.
JMO.
I believe the flow is considered as not compressed, as if it was water.,
@ Any air that is forced through such a conical shape or device would be considered compressed if the pressure is raised as was shown by his metering device.
@@evil17 I am trying to differentiate between under pressure versus compressed as in a volume change. If you think of water flow you don’t think of a volume change, but you still have the pressure changes due to flow through the nozzle. Was the water compressed, or was there a pressure change? Now extend that to the airflow.
This presenter reminds me of Nikolai Kuznetsov, the Soviet-era chief designer of OKB 276, the development center that designed many of the highest-performance jet engines of the cold war, and also the NK-33 rocket engine (still in use today as the Aerojet AJ-27). When built, the NK-33 was the most thermodynamically efficient rocket engine in the world, a title it held for over half a century until the Space X Merlin.
ure saying elon musk built an engine that has beaten something designed by a soviet era guy who looked like an AI version of a real life shrek 🤣
There is so much you are missing, it is amazing.
and yet you haven't managed to define or elaborate on a single one. Quite stunning. - The arrogance, I mean.
@@gurglejug627 _"and yet you haven't managed to define or elaborate on a single one."_ Because people like you that couldn't possibly understand the basics, would be like talking with a wall explaining the complex that you are missing.
Oh, please, do elaborate. I mean he's not talking quantum physics here. And barely brushes on particle physics. It's simply fluid dynamics in relation to atmospheric pressure throughout a constricted path.
Granted, air/fluid velocity should have been discussed in more detail but as an overview I think it was rather well done
@@villainbydesign _"Oh, please, do elaborate."_ Oh... I did... I explained in detail to They/Them gurglejug62d7, just under They/Thems comment. In about 200 to 300 words. It hurt their feelings so much that they/them reported it to YT as "Hate" speech and it was deleted.
Please explain to us all what you are not missing, and I'll go into detail what you are missing. That is after I have your comment deleted by YT as "Hate" speech... What? It is only okay for delusional people like you to have comments that hurt your feelings deleted as "Hate" speech??? Yea, we know none of you are for freedom of speech... Well, you are... Just freedom of speech that doesn't hurt your feelings.
Great video!
Why is there a paradox? The increase in the flow rate should increase the backpressure to resist it due to the restriction. Eventually, the a rise in backpressure should result in a negative pressure within the restriction. When you add a recovering combustion cycle between the pressure zones, this becomes a completely different fluid cycle, and the restriction induces a region of focused high pressure at its exit.
Sir: I watched thinking "What is the big deal, he's created an incomplete venturi." In my dad's first airplane, we would not have gyros without a vacuum. The Venturi engages Bernoulli's Theory. The Venturi converted some of the forward motion energy into outflow from a system of tubing connected attitude and direction gyro instruments.
Do you think there's something counter-intuitive in the venturi tube or Bernouilli's theorem? Pressure increases when speed decreases? HVAC field tech manager POV.... Many people have a hard time wrapping their heads around that one.
@@Kansika The sum of the static and dynamic pressures stay constant.
@@aeomaster32 What do you mean?
I usually measure air velocity in a duct with a pitot-tube connected to a digital manometer.
The volume and velocity of the flow can be calculated from the difference between static and dynamic pressures when the duct diameter is known.
Static and dynamic/impact pressures are equal when there is no flow. That's why you can't tell whether air is moving or not, not to mention calculating it's velocity, from static measurements only. You need at least a pressure differential across a quantified restriction in the duct.
Static pressure is the same in all directions and equals dynamic.pressure only when the medium is standing.still.
@ I was not challenging you, but considering what happens at the choke point of a venturi. At its narrowest point the airflow speeds up (increase in dynamic pressure) and the static pressure simultaneously drops at that point. The sum of the lower static and higher dynamic pressure should be the same as free atmospheric pressure.
Airflow over the top surface of a curved wing section speeds up (dynamic pressure) over the curve (like a veturi) and there is a drop in static pressure there causing the higher atmospheric pressure under the wing to lift it up.
@ A wing doesn't generate lift by itself and a venturi doesn't generate more flow than what's put in. Small pockets of minute low pressure at the outlet don't add to the system or create thrust although the air molecules are slightly accelerated.
The relationship between air volume and the required static pressure and motor power is staggering : to increase air volume 2 times pressure needs to increase 4 times and motor power 6 times. A venturi is a deliberate restriction of a certain known magnitude with known coefficients that consumes the energy of optimal near-laminar flow.
He does mention surface friction as a factor but doesn't address more important ones, e.g. the way air behaves when it's forced to compress and converge. Air molecules that enter the funnel are being deflected inwards towards the same axis and the steeper the angle of the taper gets the more they interfere with the main axis of flow and each other, create turbulance, and some are reflected backward so the flow is partly reversed.
The turbulent air might give you high pressure readings because there's so many air molecules pushed together and in different directions. Both the volume and velocity of the air flow are greatly reduced in the funnel and what is eventually slightly accelerated by the low pressure zone at the outlet is minimal in volume, energy, thrust, how ever you want see it. High speed doesn't equal high power or addition of energy.
There can be no equation when the amount of energy put in or coming out of the system is not known.
People are complaining, but are not realizing what a wonder they are seeing.
This is a russian speaker, who has had their language translated, with their lips synced, in THEIR natural voice!
This has effectively eliminated the language barrier!
This is just INSANE. If someone is complaining about this they are NOT understanding how useful this will be in the future! Right now actually. This will eliminate the advantage english speaking nations have during negotiations, entertainment, and so on.
Great video, just a little short but you cant learn everything about in just a single one. I expect further videos on fluid dynamics Already suscribed!!
Thanks, stay tuned for more.
It seems obvious to me that when the air enters the wide gap, it meets resistance and seeks the easiest way out. This creates turbulance ad air seeks to back out while crashing into incoming air. It would seem intuitive that the increased pressure would force air through the narrow side, but in my mind, the turbulance increases as you get further along the narrow passage, thus the drop in pressure. The turbulace and the higher pressure would seem to create an invisible bulge in front of the wide end, diverting incoming air to the sides of the tube. Spill over turbulance, being driven back over the outer wall of the tube accounts for the lower pressure there.
What I would be interested in seeing is if there would be a pocket of lower air pressure out in front of the wide end, out beyond where the higher pressure from the tube could be sustained. It wouldn't surprise me if the diversion of the incoming air to the sides creates a small pocket of low pressure somewhere out in the open air.
As for turning the tube the other way. I think the key will be the air flowing along the outside. Whether it is turbulant or slightly higher pressure, I think the big effect will be when it blows past the edge of the wide end. This will naturally drag air out from the tube, creating a vaccum, I think. The low pressure though may cause a feedback pulse. As the pressure drops, it will cause air to be pulled in from the narrow end quicker. As this happens, it will reduce the pressure in front ot the narrow end, which will take pressure from the air going along the outside, which will reduce the vaccum effect in the wide end. Thus the narrow end pressure will rise impeding air tlow, imcreasing pressure in front, increasing pressure along the outside. This returns us to imcreasing the vacuum in the wide end again. It wouldn't surprise me if this generates a mild whomp whomp sound as the air flows and the pressures cycle around the tube.
Tbis is of course wild speculation, so it is likely to be all wrong.
Thank you for the visual. I can't even imagine the math let alone do it. But I do see way the exiting air is cooler. Thanx.
Would assume in reverse that the entering air still spreads out, pressure drops and then drops further in second segment of the pipe.
Eh... kind of... to a point... if your geometry is perfect... 😅
Most of the time viscosity has something to say about it and you very quickly enter the chaotic realm of turbulence modelling. Flow separation is a major headache.
- This paradox is the problem with most attempts to duct wind turbines - Downstream flow is key not upstream, in passive systems.
The presumed ram effect tends to cause freestream air to flow around the positive pressure gradient...
First, the work done on the air by the larger portion of the tube is equal to the output of smaller exit of the tube. The liquid\gas can accellerate in the smaller exit, but it is not creating any work. Rather, the pressure must equalize before and after the "engine" and since there is no additional work being done on the air in the pressure chamber, there is no net force of accelleration, only drag due to turbulence. If the cone is reversed, the pressure will increase at the opening of the smaller tube, then drop below atmospheric pressure inside the widening chamber. A great deal of turbulence is created at the rear of the reversed or widening tube. In this case, the work done on the outside of the engine reduces pressure, and relative pressure inside the engine is even lower or equal to the airfoil effect on the widening portion of the tube--as it straitens out.
Great shirt!!!
8:19
This part fucking sends me. I am in tears.
this video is art.
The energy to accelerate the air comes from its internal energy. That's why the pressure decreases. Part of the Brownian motion of the air molecules becomes coherent motion.
The content is what’s importent …I like him…
In this video, the velocity of the air inside the outlet tube is definitely greater than the velocity inside the inlet tube. There is no doubt about it. Because the pressure inside the inlet tube will be higher than atmospheric pressure. If you blow the inlet of this tube with a fan like in the video.
If we put this tube in a wind tunnel, the inlet pressure should also be higher than the outlet pressure.
Will there be a reaction force at the outlet of the tube? it will be. But this reaction force is not acting on the tube, but on the air. So it cannot become the engine of an airplane.
You know narrowing conical shapes are used in supersonic jet engines to slow down the incoming air? An increase in pressure, i.e. narrowing of the tube, slows the air down so it's suitable for the rotor. The air speeds up when pressure eventually drops at the outlet.
@@Kansika Is slowing down the speed an increase in pressure?
@@enbinzheng-line Yes. "Bernoulli's principle states that an increase in the speed of a parcel of fluid occurs simultaneously with a decrease in ... pressure." Notice that it doesn't say that lowering the pressure at source of the flow will always increase the speed of the medium downstream. Additionally all this applies to static pressure which he is trying to measure here.
It's quite logical when you get your head around it. Try this: a high speed flow of air in a duct meets a restriction and is forced in to a narrower duct. Of course the flow will slow down bc all that air won't fit in as easily. Simultaniously the pressure it exerts on the walls of the duct is increased bc the same mass has to fit in to a smaller space. And vice versa, when the duct opens up to a larger diameter the air speeds up while the presuure it exerts on the walls decreases.
@@Kansika What you said is incorrect. The fluid is continuous. Assuming the fluid is incompressible, the volumetric flow rate inside the tube is constant, so the fluid velocity at the inlet of the converging tube must be lower than that at the outlet.
@ There's no incompressible variables here. What he theorizes, models and measures don't add up. Why not set up a venturi tube yourself and test if Bernoulli was wrong?
First of all the CAD model shows a cone with an even diameter extension nearly as long as the cone. The model he built only has a cone and an outlet. Not the same thing. A taper or a restriction always causes turbulance that takes a while to settle.
Secondly he's holding the end of the probe tube away from the direction of flow. Air flowing over tuhe tube creates an eddy flow at the tip creating negative pressure zones.
The least he could do would be to take more readings with the nozzle facing the flow. That would be the dynamic pressure and subtracted from the static pressure it might give some hints about air velocity. But like I said he's not measuring static or dynamic presuure here.
I use a pitot-tube with a digital manometer to test ultra-sonic air flow sensors at work. Turbulent air is very hard to measure. All and all, air speed is not what he measured here.
This video reminds me a little bit of another video on optimal feeding of ball bearings through a hopper.
Although the principles are not exactly the same, I can see where the taper of the funnel has importance.
To add a spin of sorts... pressure converts to flow and the reverse. We need to measure both to get a picture. If the fluid slows the pressure will rise. If the fluid increases speed in the narrowing part... it should have a lower pressure.
Isn't this the Bernoulli principle? Believe it's been thoroughly explored and documented.
This is devastating news for the free energy community. 😊👍
At first thought the conundrum is solved by the additional thrust of the plane we are riding on required to make up for the overall drag of the device.
Without any study in physics it seems to me the funnel restricts the air flow if placed in either direction, except for the line of travel directly straight through the small opening of the funnel. When the large opening of funnel faces the oncoming flow of air it allows more mass of air in and creates higher pressure and air velocity out the small opening of funnel. If funnel was in opposite direction, the ambient air would be diverted around the outside of the funnel and no higher pressure would result.
Video is excellent and educational (for younger especially). But, from the title "paradox", = it is not paradox, paradox is something which happens very rare or out of something you see every time of often or out of all the time. (but to rise interest in physics, it is good)
It is normal matter density to make balance, (it is with harder matter example: if you remove 2/3-rds from cup with water, normally 1/3-rd stays. Even it looks funny to many, because is normal) when same air in one part of pipe becomes more dense - just near it has to become bellow normal density - because it has to take it from somewhere. So, paradox would be: if everywhere becomes more density and rest to be normal density, that would be: "from where more matter suddenly".
Isn't this an example of compressor stall?
The gentleman first described this as a free energy device. In other words, a perpetual motion machine. That is simply not possible. The air exiting the narrowed tube does produce a forward force, but the drag created by the constriction is greater.
A pair docks is where I keep my two yachts.
Vape wave not naw, correct?
in your dreams...
This was very interesting for me as I had a practical example, and this explains why it failed. I had assumed it was drag. As an experiment I purchased a drogue or sea anchor, a large canvas funnel 60 cm wide end, 6 cm narrow end. I expected that when set-up in a slow moving creek, I would get enough exit velocity (minus drag) to run a river gold sluice or even a high-banker. It made for a good facebook joke though: 'I am now the proud owner of a drogue (image) They told me I ought'a buy a boat first, but I like to do things differently!'
well done. thank you.
Is going to create a vacuum on the outside a vortex, drawing the air in. There's always an equal opposite reaction there Together
You left out
Bernellies theorem states that as pressure increases velocity decreases, and vice versa it is the main theory for jet engine operation. ✌🏻🇺🇸
It is better to refer to pressure by its components. Total pressure is constant unless energy is added but the static and dynamic pressure can be exchanged without adding energy. When you slow the air it's static pressure goes up but it's dynamic pressure goes down and vice versa when you speed it up but the sum of the two, which is the total pressure, is always constant. This remains true until the air becomes considered compressible usually above Mach 0.5 and higher.
When the cone is flipped my guess is there would be increased atmospheres at the entrance, as the laminer flow around the exit essentially grabs hold of what's coming through the cone.
At a guess, reversing the air flow direction would be, to first order, like running the original in time reverse so the pressures would be identically distributed. Frictional forces aren't time reversible so there'd be some differences.
I expect the dynamical explanation would feel very different though from for the original.
This is that new george droyd ai with the nigalink interface powered by a fent reactor. Amazing
I see an error in your test where you measured air pressure over/below atmospheric. Your exit did not have a tube like your model did, that is why you never saw the negative pressure your computer model predicted.
Bernoulli’s theory says if you restrict the flow of a fluid, velocity increases and pressure falls.
Since there was no long tube in your exit, the restriction disappeared too soon for you to measure the reduced pressure caused by the increased flow inside the restriction.
You actually did measure a bit of negative pressure but the tube was not long enough to show it definitively.
Try it, you will see I’m correct.
As a measurement technician I studied this effect in school as we use this same effect in industry to measure flow inside pipelines. We introduce a precision restriction inside the pipe and measure the pressure upstream and downstream and can accurately measure volumetric flow.
Vortex pockets might form in the wider end of the pipe, so that the continuous stream of the fluid do not follow the crosssection of the pipe.
When fluid flow exits a pipe at subsonic speed into a large reservoir, it forms a jet and the static pressure at the exit plane inside the jet MUST be equal to the static pressure outside the jet, which is the pressure in the reservoir. This can be proven by the following reasoning. Let's keep it simple by assuming inviscid incompressible flow; i.e., no friction with the Mach number squared much less than unity.
First, let's assume the exit pressure in the jet is above the reservoir pressure. That means the jet must expand as it enters the reservoir, which in turn means the flow area of the jet increases along the jet. If the area increases, the continuity equation requires that the flow velocity must decrease, and the incompressible Bernoulli equation requires that the pressure in the jet increases. Using the same reasoning for points further downstream of the jet, we realize that the pressure in the jet will always increase and never reach the reservoir pressure. This is impossible.
If we assume the exit pressure in the jet is lower than the reservoir pressure, the flow area must decrease, resulting in an increase in velocity and a decrease in jet pressure, meaning that the jet pressure would always decrease and never reach the reservoir pressure. This is also impossible.
The only physical result is that the exit jet pressure must be equal to the reservoir pressure. Thus, the pressure at the entrance to the larger diameter end is a little higher than the reservoir pressure because some of the kinetic energy (0.5 Rho V^2)of the free stream flow is converted to potential energy, or pressure, because the tube is an obstruction.
I thus conclude that the figure showing the magnetic flux lines is incorrect.
When the tube is turned around, we can reason that the exit pressure in the jet leaving the larger diameter end must again, as before, be equal to the reservoir static pressure. That exit pressure must be larger than the pressure at the entrance to the smaller diameter end, because the tube is acting as a diffuser - fluid flow with increasing diameter, using the same equations of conservation of mass and Bernoulli (conservation of mechanical energy). This latter fact leads us to conclude that the entrance pressure at the smaller end must be a little lower than the reservoir pressure.
Thanks for the interesting discussion.
I am amazed that i found this video purely by accident. I have maybe a kind of inverse paradox that might be very similar. Can you explore this for me?
I had a need for a very small but strong vacuum cleaning device. I put an inverse funnel shaped attachment on a very powerful shop-vac vacuum cleaner, and had the cleaning tube side with a very small maybe 4mm opening (it was some narrow plastic tubing). In my mind I was expecting the tube would suck air very strongly, kind of like the dentist uses. The paradox was, it felt very weak, that powerful shop-vac motor was straining but could not provide the results I wanted.
If the pressure in the cylinder were below atmospheric, then the higher pressure of the atmosphere aft of the cylinder would cause air to enter from the back to equalise the pressure.
I'm guessing there would be some flow separation of the front to rear airflow towards the end of the cylinder's inner surface.
lol. couldn't hear above the blower noise.
This is the result of AI translation.
The "paradox" is never resolved. Of course there never was one to begin with, because comparing the velocity of the air doesn't cut it. The comparison should incorporate flux as well.
On another note, the reduced pressure in the narrow tube is to be expected as this is basically a venturi tube.
I missed some of the vital information because of the bloody vacuum cleaner. However my prediction is that in the reversed pipe an area of high pressure will form as the air flow slows down. 😊
Who is he? He's very competent. Good knowledge and explanation.
You forgot that air have no laminate flow and also temperature hot spots put also into account the angle of the reverse flow perpendicular to the angle of attack inside and outside the jet tube
Further the inlet conform whatever form have to have a maximum inlet degree of10 ,all in all there will be no gain in flow unless creating an artificial low pressure at the end
7:00 A better explanation of what the colors signify is definitely needed at his point. The viewer is forced to infer what colors are higher and what colors are lower.
My question is where in the airstream did you take your pressure measurements, it was difficult to see. Were they in the center, off center, or near the wall? I would like to see some lateral pressure measurements from wall to wall at several distances in the cone.
This video told me how the nature of things is one of the best parts of living on GOD's earth.
Happy New Year Sir too. Peace vf 😀😀😀😀
I'm thinking out loud, no shade on you at all. If its sitting on top of a plane, there IS energy input with it sitting on a plane. the moving plane is giving it energy. wouldn't it create a vacuum at the inside of the taper? Now that you showed me the vismach i understand the airflow. VISMACH as in linuxcnc vismach? where are you getting the vismach program from? As far as it being an "engine", IMO, the losses due to friction would make it essentially useless as an engine. I'm trying to think of some proctical use cases........Great experiment. Guess what? You get a like, comment, and subscribe.
Glad you enjoyed it!
6:41: How come there is a blue patch in the further most right of the tube where distance between two adjacent streamlines is decreasing? I would expect blue to the right of central stream, where the meter showed it. It seems another virtual funnel will be opening up to the right of exit.
8:20 this is known as the Maxwell Smart, Cone of Silence, part of the video.
Cool video for reasoning dynamics, but there is nothing close to a paradox. It's a paradox if you don't calculate either the energy in the wind from the model, or the torque from the plane in the hypothetical.
You could with the same success demonstrate that peas dropped in the funnel fly out faster on a bottom than enter it at the top and argue that this should mean that the funnel might fly upwards due to pea jet stream.
If you reversed the funnel in the air, I believe it would have normal pressure in the narrow part and lower in the wider.
I hate being swarmed by gnats when I'm trying to explain physics
Even worse if they are invisible. How are you supposed to swat them?
If someone is talking about a paradox, it simply means they dont understand. Not only do they not understand the subject matter, they dont understand what a paradox is. This is not a paradox. Also, "Neural translated" is not a sufficient declaration that the video material is produced using AI.
Neural translation but not AI? And I hear that guy talking ( These are 3 paradoxes!)
An increase in pressure means resistance...... A decrease in pressure it means flow......
I think if we reverse the engine a small vacuum is created at the end of the large nozzle, pulling the air through even faster. Yes/no?
I'm not really sure it's an actual paradox as much as a counter-intuitive phenomenon.
When flowing air is compressed in to a narrow channel it's pressure increases and it's speed decreases.
The highest pressure measurements mean the slowest air speeds. When the pressure drops again the air speed increases. Add a combustion element to that and you have a jet engine. In supersonic jet engines the intake nozzle and cone work to slow down the incoming air to sub-sonic so the engine can handle it. The decrease in pressure amplified by the combustion gases at the outlet nozzle give the air it's super-sonic speed.
a parachute is a funnel with a hole at the top. this should accelerate the parachutist toward the ground.
Best way to beat it, is get a pair of shoes and forget the dox.
Next up: the tapering paycheck paradox.
Imagine two pipes of different diameters connected by a smooth adapter. Now let us place this structure in the air flow with its wide end forward or, what is the same, move it relative to the stationary air. The flow enters the wide part of the tube, then passes into the narrow part, and at the same time, obviously, increases its velocity. Have we really got an air gas pedal, a kind of jet engine that runs without any fuel?! Something's not right here.
A metaphysician like Newton will immediately say that the Creator of all things so arranged the universe that man could not get something for nothing, and such an engine is a priori impossible.
And a physicist (like Newton) should find an error in this very plausible reasoning and understand in what exactly we deceive ourselves.
Let's follow the air pressure along the axis of the pipe. Behind, at the exit from the narrow pipe, the pressure is atmospheric, as well as inside it: the air flies there by inertia. But in the adapter and in front of it, the pressure must be greater than atmospheric to drive the air into the narrow pipe and increase its speed. But before the wide pipe the pressure is again atmospheric, so at the entrance to the pipe in the area where the pressure increases, the air flow slows down and expands.
So far ahead of the pipe, the cross-sectional area of the flow that will then enter the pipe is smaller than the cross-sectional area of the wide pipe and probably equal to the cross-sectional area of the narrow pipe. Then there is no acceleration of the air - with what speed the air moved far ahead of the wide pipe, with the same speed it flows out of the narrow pipe from behind.
Here, as in other cases where we encounter seeming paradoxes, it is important to draw the lines of current correctly. For example, the wing of an airplane not only deflects the airflow downward behind the trailing edge, but also causes it to run into the leading edge from bottom to top, rather than horizontally. Or else: water moves much faster in the inside of a pipe bend than on the outside.
And as in many videos devoted to hydrodynamics, we simulate the flow of our “engine” using the Vizimag program, because the mathematical equations describing the motion of an ideal fluid and a magnetic field are exactly the same.
Reminds me a bit of ramjet theory
And it opens the door to next paradox: What happens above the speed of sound, when the pressure from the tapering cannot propagate to the entrance?
This is terrifying,
Seems odd to explain pressure without bringing up the inverse relationship of volume. What about the effect of heat on the pressures of a jet engine? Finally, what about what a cross-sectional view of the tapered pipe showing the different rates of flow? Is the rate of flow universal across and throughout the pipe? In an ICE with a turbo or supercharger where the flow is externally induced the effect is call boost.
Try 2 study V.Schauberger or H.M.Coanda, in what form/shape is air moving, spiral wave, vortex flow,
Paradox, hmmm... only if U chose it 2 be👍
Love this kind of thing ? How dus the venturi effect play a role ? It must speed up the flow on the way out right ?
The probe is creating its own Enomalies.
There's no way this guy has a physics background.
there is no way you can watch this and believe it is a real guy.
You will have an increase in velocity in the tube but no thrust....as it is just a tapered tube...increase the velocity of the tube to mack 2 add some atom Atomized fuel and you have a scram jet.