Bernoulli's principle
2021 ж. 26 Қар.
1 553 480 Рет қаралды
The narrower the pipe section, the lower the pressure in the liquid or gas flowing through this section. This paradoxical fact, following from the law of conservation of energy, is called the Bernoulli principle or law.
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This principle humbled me as a young scientist and student pilot. I thought I knew everything, that I had an intuitive grasp of basic physics. It took me a long time to wrap my head around this one principle.
Good to hear! We should never assume that we know everything of anything. This video was indeed quite intersting.
It seems to make more sense for me to realize the air being blown is sticky and grabs the air from the side tube and pulls it along. Mayne not correct but hey I'm just a regular joe
Yes, that’s a good way to think of it. It makes more logical sense to me the way you’ve described the ‘sticky air’. I’ll remember that.
This is literally what I study in Highschools. This principle is one of the basics.
Physics is the discipline where math proves common sense totally wrong.
The interesting part is that if you close the system, when you blow, pressure increases. However, when you open so that the air can flow, the pressure decrease the faster it goes.
I've just finished reading James Burke's superb book Connections, which I would recommend to anyone interested in the history of scientific ideas. In this book he explains how this principle was used to create carburettors, making possible the internal combustion engine and jet engines, and how the principle it could be used to measure the flow of a gas through a pipe. However, limited space only allowed him to give a brief overview of these things. The excellent demonstrations in your video make it easy to get my head around these concepts.
The TV series Connections is superb, as well. I highly recommend it.
Great demonstrations of Bernoulli's principle! Seeing the effect in action helps to understand it.
Unfortunatly, it is WRONG. Please make corrections or remove it. .. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel are a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
Same thing happens when high-pressure information passes through my low-pressure brain
What, it pushes your balls together? (sorry; couldn't resist)
This video is awesome! It explains teh principle in a simple way, as well as showing *how* it works and demonstration of the use
Beautifully explained. One of the best videos on Bernoulli's principle on KZhead.
You just made a carburetor.
Damb it you beat me to it lmao
And an air brush.
I thought it was a bong. But I ain’t that smart. 😂
Merge collector 😎
Syphon hose
An excellent learning aide. Very well done.
That was the best lecture I have ever seen.
Please make more videos. 🙏 Doing so will increase the likelihood of young minds coming across valuable information such as this. 🧠🧠🧠🧠🧠🧠🧠🧠🧠
Excellent video, thank you for sharing this!!!
This seems rather unintuitive, but you explained it very clearly. Thank you.
What a superb video lesson. Very clear and engaging. Many thanks. 😊
But WRONG. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel age a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
Venturi, excellent illustration.
This phenomenon is one of the most mind- fucking results in all physics to me. The fact that blowing air with high pressure through a tube with a restriction causes the air to decrease in pressure at the restricted part is so counterintuitive. My brain just will not understand how increasing the space in which a fluid can flow causes the pressure of the fluid to increase and vice versa.
Excellent demonstrations. best wishes for your channel growth
Best explanation of Bernoulli's principle I came across on internet. Thank you so much!!
Comical. EVERY video on this topic has the exact same explanation: "narrower the pipe section, the lower the pressure" because equations . What happens is equations due to more equations . HOW does it work? By equations .
@@billshiff2060 Buddy, the equations explain exactly why this occurs. The velocity of the fluid increases as it travels from a wider region to a narrower region, as the work done by the fluid is down a pressure gradient. Therefore, the fluid must flow from a region of a higher cross-sectional area to a narrow cross-sectional area in order to increase its velocity, and this would naturally cause the pressure exerted by the fluid to decrease. Mathematical equations simply explain this phenomenon through variables instead of words.
@@weltschmerzistofthaufig2440 So your explanation is, it is caused "naturally" + equations. No mention of particle velocity, which IS the cause of pressure, is ~ mach 1.5 regardless of where it is and yet the pressure decreases in smaller passages.
@@billshiff2060 Are you saying that Bernoulli’s principle doesn’t work? I could use kinetic particle theory to explain it, but I instead focused on macroscopic observations and mathematical evaluation to explain this. Also, who told you that particle velocity remains the same? In fact, in a narrower section, the total number of collisions between particles and the container would decrease as the work done by the fluid occurs in the direction of movement. Thus, a pressure gradient must exist to ensure that there is an increase in kinetic energy in a narrower region.
@@weltschmerzistofthaufig2440 Who told you that particle velocity varies?
In realms of air where wings take flight, A dance of forces, pure and bright. Bernoulli whispered secrets old, In currents swift, a tale unfolds. Above, below, a magic play, In skies where dreams find their own way. A symphony of pressure and speed, A waltz unseen, the laws decreed. As air flows, it weaves a song, A melody where forces throng. Upon the wings of birds in flight, Bernoulli's dance, a graceful height. At curves and bends, in fluid grace, The air, a partner in this chase. Velocity and pressure dance, In every move, a sweet romance. From wings that lift to planes that soar, A principle forevermore. In tubes, in winds, in rivers wide, Bernoulli's truth, an endless guide. A theorem sung in skies so blue, In clouds and dreams, forever true. A whispered secret, nature's rhyme, Bernoulli's principle, through space and time.
I love this!! ❤
ChatGPT?
Me, using ChatGPT 😄@@bindum7178
This felt like something straight out of Ace Combat. ❤
Yes, very obviously ChatGPT
Fascinating video. However, I am not sure that the ball hanging in the water coming from a tap is really demonstrating the Bernoulli principle. Firstly, the water is not being constrained to flow through a narrower channel - it is free to flow over the surface of the ball and so the cross section of the flow is probably not reduced. Secondly, if you look at the flow of water coming off the bottom of the ball, it is deflected to the right after it has flowed over the surface of the ball. Changing the direction of the water flow to the right causes a reactive force on the ball towards the left, and this is probably what makes the ball appear to cling to the water - the ball comes to a rest where this leftward force is balanced by the rightward force of the downward water flow pushing on the ball.
I agree that the ball in the running water was not explained right or enough. But I think they meant that the change in the pressure of AIR around the running water causes the movement of the ball, not the pressure of the water. For some years now I have wanted to know why the spoon is pulled by the running water. And to me it looks like the curved shape plays the major role. I doesn't happen when you rinse a knife.
@@sylwiagotzman5422 Have a look at the video: Why are so many pilots wrong about Bernoulli’s Principle? by Fly with Magnar (kzhead.info/sun/qN2LqJZthIWNoZ8/bejne.html). IMO he explains quite well what you're describing, it is the same as for an airfoil. Spoiler: it is also Bernoulli's Principle, and has indeed to do with acceleration of the fluid at the convex part of the spoon
It's the Coanda effect, not Bernoulli's Principle, that pulls the spheres or spoons together in a liquid or gas flow. The experiment would not be able to be replicated with cubes instead of spheres.
Very simplified demonstration of the basic principle of Bernoulli .I wish some body could have explained me in my school level in such a lucid language.
This is counterintuitive. How did I live these whole years without knowing? How many more are out there that I think I know but I don't? Holy Castana!
Beautiful video. What a cozy nice accent. I loved it.
Very nice work
This just blew my mind.
I would have loved to have seen this video as my younger self, it explains perfectly why airplane wings work
That's one of the educating channels you subscribe to.. once a fan of science always a fan of science
So... the two balls were "sucked" towards each other because the two balls created a small channel for air or water to pass, thus creating lower pressure compared surrounding space (atmospheric pressure). This lower pressure in this smaller channel creates a vaccum, pulling the balls together.
Kind of. The higher pressure on the outsides push the balls together. There's no "pulling".
Fantastic use of the word _thus._ 😄
A pressure difference in stead of a vacuum.
Yeah i think it's also due the the specific shape of the sphere.
it's not the vacuum that pulls the balls. You've said it: it's the atmospheric pressure that pushes them. __ for a 3 cm radius sphere we get about 1 N: P=f/A; f=PA = 101 Pa * 4Pir^2 =101*0.0113=~1 N
Finally a good explanation of Bernoulli's principle
I think that this didn't explain the nature of the effect - the *behavior* of the particles (or strings) in flow relative to "stationary" ones. A part two to the video, with particle animation, where you visualize the pressure exerted by particles which do not flow is very much needed in my opinion.
The video is great and makes it clear how the pressure works for air and liquids and such, but how would the joined trumpet shapes react to sound. If one half is similar to the old ear trumpets that increased the sound, is this saying that the increase in sound is similar to the speed pf water, and that the increase in sound is matched by a decrease in some other quality of sound.
You made my echocardiogram studies easier, thank you
What ? Hiwnplz
I mean how plz
The correct term is to say `Bernoulli's' Integral', since it is just an integral of the Euler's equations of motion for a particular case of steady, inviscid and potential flow. The term `principle' is related to something very fundamental, like The Principle of Least Action etc.
I honestly hope nobody is watching this video for Education purposes. Because my soul died in the first 2 minutes
That name is popularly known by people. You can get the same equation by cancelling viscous terms and triple integrating Navier-Stokes' momentum equation. If I can do that, then it should be called the Navier-Stokes-Bernoulli equation, and it's not that A name is just that, a name, so people can easily recognize the equation
Right on smarty pants, well explained and demos. Nice job!
I had to subscribe! Amazing video!
Very nicely explained basics.
Excellent..!
The pressure reduction is due to the expanding exit and not the narrow part of the system. The width of the entry may not be important but the exit, the wide exit creates a sudden increased volume hence the reduced pressure. I would like to see the same experiment be done without the expanding exit and see if there will be any differences
now this got my interest, you explained it better sir 👌
The exit or diffuser has been measured (not estimated) countless times to have increase in pressure, the negative peak of pr3ssure coefficient is at most right before it, if your brainstorm was close to right the entire racing industry would be incorrect.
That happens at supersonic speeds
I worked on an evaporator the use the Venturi Effect powered by low pressure steam jets.
I have an interview question (for the post of nuclear scientist ) on this principle. Qsn)can we use the pressure sensors at throat and diverging sections gives the same result . Qsn)do this arrangement give same result as traditional arrangement (pressure sensors at converging and throat section).
I really LOVE this video Back in the 80s we had Bernoulli Boxes These were large (for the time) memory disks using the Bernoulli principle I know you have a large queue of ideas, but could you please put a video talking about this video along with one explaining the Bernoulli Box?
that's hilarous
The first demonstration (with the 2 balls) perfectly explains porpoising in Formula 1.
I love this woman's voice.
Muito boa a explicação. Obrigado! Para quem não entendeu o final, em 4:50 a velocidade é calculada dividindo o "volume de ar por segundo" (12 l/s = 12000 cm3/s) pela "área da seção" (3 cm2) = 4000 cm/s = 40m/s
Flow is displacing molecules between. Thus, flow displaced by volume pushes molecules.
The flow of a liquid or gas following along the outside of a curved surface is the COANDA EFFECT!
thanks a lot, the physics is wonderful
Merci Bernouille !
very nice presentation.
An Air brush functions by a certain velocity of air passing laterally down a tube of said diameter - at a mid point down the tube is a T- piece with a pipe leading to a semi liquid media /paint source - A pressure is formed at the pipe perpendicular to the main pipe due to currents being generated by the air flowing through the lateral pipe. The flow of current in turn causes a vacuum at the pipe perpendicular to it. - With a carburettor this is called down-draft. Its basically a pressure created by many things travelling at speed - Aircraft, Cars, Speed Boats - - If you have wondered why if you leave your tail gate open you get chocked by exhaust fumes being sucked back into the car.
Good channel needs more subs.
One of the clearest explanations of Bernoulli's Principle that I have seen. Everything very well explained, and many examples showing how everything works. Thank you very much!
All Jet engines work on this principle on convergent and divergent ducts.
Randomly stumbled to this video and thankfully I clicked it. Now I understand how the soap get used when my father use the his pressure washer with bottle of soap on the water gun.
Great video You made my day with this
Glad you enjoyed it
3:00 and there you have a CARBURATOR!
I just wish someone would taught me like this when i was young.. when KZhead was not that much a big hit and we had to pay exorbitant prices for just 1GB of internet data in India at that point of time we had to imagine all we could.. but now seeing this animated video with real life examples is what giving me an epiphany that what i imagined at that point of time was correct…
Do you know the auto stop mechanism of gas pump to prevent spill over is based on Bernoulli's principle?
I have always had difficulty providing an intuitive explanation for this phenomenon, but if we try to think of pressure as potential energy rather than force per unit of surface area, perhaps the concept becomes a bit more intuitive. Or, imagine having a blown-up balloon. The balloon has a certain internal pressure. When the balloon is opened, the air inside the balloon starts to move faster. The internal pressure of the balloon then decreases because the potential energy of the air inside the balloon is converted into kinetic energy.
Good analogy
You have to embrace pressure to reach your full potential.
As the speed of the air increases the ball redirecting the air has a boundary layer that causes the air to follow the curved surface . Air has weight . The air is acting under the laws of Centrifugal force as it is held to the ball by the low pressure boundary layer and causes what we call lift. Air accelerated across a curved surface "wing" creates lift by the weight of the centrifugal force directly relative to the speed . The faster the wing through that air the faster the air has to move to follow the wings surface which creates centrifugal force by kinetic energy. A wing flying just above VSO can not be over stressed . But above VNO can be overstressed easily . More airspeed across the wing more centrifugal force the air creates on the boundary layer. Such an experiment if I remember correctly was conducted on an F16 wing with a porous top wing surface where more vacuum was introduced I would suppose to slow the stall break. Boundary layers lifts NOTHING . It is the area between the wings surface and the fluid movement of air which can not do anything above VSO but adhere to the upper wing surface curvature creating a vacuum across the wing . The blunt nose of the wing along with angle of incidence only accelerares that air. The Whittman wing for the Tail wind has a thin wing with a sharp leading edge thus high take off , stall and flying speed. Ultralights use a very rounded leading edge to compress the air flow across the wing this a low stall speed .
This is great!
This video is WRONG. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel age a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
MIND BLOWN
Offshore, we use the kinetic energy of a fast flowing water as pump, we call this process an ejector...
The case of the liquid faucet and the ball may conflated with Coanda effect
What about the speed of the flow in the narrow section ?
If P1 and P2 are different then how come fluid volume (say gas) remain the same at those two points ?
A Venturi. Used in some priming pumps.
Your test tube is after the smallest opening, so the pressure is decreasing. The pressure increases to the maximum AT the smallest opening. It increases, then decreases suddenly like a divergent rocket nozzle trading pressure for flow/thrust. Like a transformer trading voltage and current with the power being the same except for the small loss of the transformer.
Well done!
V2 is smaller than v1
I'm waiting. Not forever. That's the message.
🔥🔥🔥Amazing work 🔥🔥👍👍
This video is WRONG. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel age a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
Intelligent video how to make a Bernoulli bong.
This is how a carburetor works.
This demonstration also covers the Coande and Magnus effects, maybe even the Casimir effect.
THANK YOU SO MUCH!
Good explanation
If you control the sizes of both ends of the funnels carefully you can get supersonic air flow from non supersonic air flow.
When you blow on two balls the pressure can also increase so much that it can become very messy 😊
The seemingly stationary yet the active atmosphere around the two-ball system pushes the ball to come together when the air in between them is displaced. Though the atmosphere tries to fill in the gap again with air, the continuous removal of air makes the balls stick together and the direction of the displacing pressure dictates the direction of the balls' rotation.
👑for you my unsung hero
Is it same for liquid? or what changers?
Thank you so much; Really awesome! But why did you say that the volume decreases rewriting the formula of kinetic energy which is valid only if the volume is the same? Maybe I didn't get it well; can you explain, please? Thank you.
Yes that was a mistake. The fluid is considered incompressible so no change in volume (capital V) occurs. Only changes in its velocity and pressure. Also the volume disappear entirely from the equation, as shown.
Now it's clear. Thank you very much for your generous activities.
I learned nothing, but had a great time doing it.😁🤟
You can buy replacement shower heads, which promise to increase the force of the water spray at (I presume) the cost of some decrease in the total volume of water leaving the shower head in unit time. It does seem to work, but the effect is (imo) rather too feeble to bother about.
When moving at considerable speed, this principle becomes tactile; breathing with wind-force against ones face 'should' make inhalation easier by intuition; however it is not the case, the faster the wind approaching ones face the harder it is to inhale, in-fact the lungs volume is wrenched from ones throat instead, and only an eddy-of air-pressure will allow ones respiration at-speed.
It's not true that faster air flow implies lower air pressure. Bernoulli's Principle only says that a faster section of flow within the same fluid flow must have lower pressure than a slower section within that same flow. If you stick your head out of a fast moving car and face forward, it should be easy to inhale.
"the lungs volume is wrenched from ones throat" Maybe the wind was pressing against your chest too and that forced the air out of your mouth.
Constant enthalpy for open systems!
This won't ever not blow my mind
PS - this is how damage control crews on ships can pump water out of a cabin without a motor
i wish i had seen this in my college days
That is not a "paradox" nor "counterintuitive". That is a quite simple relation emerged from energy conservation principle... If you're struggling with these, perhaps you got confused over the "pressure" term - when velocity increases, the STATIC pressure is the one that decreases.
I need lots more like this|
I think Bernoulli’s guidance councillor probably had more influence than his principal....
And thats how maby not best, but most simple, and most reliable air pomp is made. Industrial usage of it is huge
2:30 try turning it around tho’. The air must have lower pressure than outside the tube…but the straw will experience +ve pressure because it is upwind of the narrowest part.
The main thing to remember why this works is cause pressure moves from high to low and the fluids follow this direction of motion
The force in the system must remain the same. If the speed increases in the narrower part, the pressure must decrease.
And similarly, if the net speed decreases, the pressure must increase, which is what happens with compressible fluids.
Is that the Venturi effect?
1:02 would the same thing happen if it's a laminar flow?
Is it legal to teach this in Florida?
Bernoulli's theorem is nothing but a application of work energy theorem