This is really cool. It's so counter-intuitive that a fluid passing through a smaller space has decreased pressure, but it's super easy to test with a hose.
@captainamericawhyso59173 жыл бұрын
Lower static pressure the dynamic pressure increases actually
@dhruvparmar40613 жыл бұрын
But how if we put hand against fast fluid it will exert higher force than slow fluid .
@E_Rico2 жыл бұрын
@@captainamericawhyso5917 what is the difference between the two?
@w花b2 жыл бұрын
@@dhruvparmar4061 you have to imagine that the whole tube in the video is filled with water and it flows from left to right, the hand thing is not a good example because it doesn't compare to what's show in the video.
@shishkabobby2 жыл бұрын
A much more intuitive way to show the Venturi effect is to show a section where the pipe widens, rather than narrows. If we double the cross sectional area, the flow rate (m/s) falls in half.
@ippys19979 жыл бұрын
Excellent explanation. Extremely useful for engineering as well.
@amandadube1565 жыл бұрын
team FE prep, what up
@theadel85914 жыл бұрын
@@jonathanstevenson8948 you and me are full of fluids, don’t you think these people studying blood circulation, blood pressure, and all kinds of bodily processes should know about how fluids work ?
@reypolice52313 жыл бұрын
@@theadel8591 All branches of science have theories that conflict with other branches of science. In this explanation he claims that a restricted or reduced diameter pipe lowers pressure. When you go to the doctor and get your blood pressure tested. He wraps a choke around your arm and inflates it with air reducing the amount of blood going through your arm or the constriction. He then tells you, your blood pressure is 80 over 120psi. showing the resting blood pressure, and the active pressure. But that wouldn't be accurate if this above theory was correct. Their measurements of so-called pressure would have to match the existing pressure in your arm but it doesn't. It's measuring the pressure of a constricted area which in this case would be the center of the pipe. So they're actually measuring the lowest pressure in your arm, but claiming they have empirical proof of what your blood pressure really is. I've yet to see one branch of a science or discipline that doesn't conflict with the theories and concepts and held beliefs of some other branch of science. Not even doctors can agree, cuz they all have separate specialties. So it's all theories and opinions, none of it is fact, And it's only a working theory as long as their so-called law has working parameters that allow it to exist. Take away the working parameters of any so-called law and watch that law fall apart. There are an awful lot of laws that require gravity, so if you do them in space the law falls apart. This was Einstein's conundrum. He wanted a theory of everything. And the stuff worked on the small scale but didn't work on the large scale and the whole thing fell apart. So as a student pay attention, these guys really have no clue what they're doing. They just have a bunch of "Theories" they call "LAWS" that really don't work, but they insist you believe them as fact, like some kind of cult. To pass their tests to get a degree, or a passing grade in a particular subject, you have to just blindly spit back the information that they give you: whether you believe it or not. So it's actually not a knowledge test it's an intelligence test. If you're intelligent enough to question their fake laws, you get a failing grade. If you don't care about what they're saying and blindly believe everything they tell you you get it passing grade. Order takers and sheeple get degrees in the academia. Question whatever they're doing and you will fail your class. By the way in hydraulics if you reduce the diameter of the pipe they claim in hydraulics that the pressure goes up. Over here in physics they're climbing that the pressure drops. So in hydraulics: in a hydraulic line, if you reduce the diameter of the pipe from what it was before then you have a higher pressure, and it'll go higher up the pipe. So in hydraulics they're not calling it more speed, they're calling it more pressure, cuz it goes higher up the pipe on a smaller diameter pipe. When the pressure stays the same but the pipe is reduced. Like I said from one discipline to the next none of it adds up. None of them talk to each other and have a uniform theory across all disciplines. The physics department does not talk to the hydraulics department, does not talk to the math department, does not talk to the science department, does not talk to the medical department.
@reypolice52313 жыл бұрын
Is this a fact that you claim proven by installing a pressure gauge at the reduced pipe section in the center? The pressure will reduce not increase at the cone shaped part after the reduced pipe in center. did anyone bother to hook up a pressure gauge at the center and at the cone shaved part after the center reduced section? Perform this test yourself and challenge this test. Do not blindly accept whatever they tell you as this does not match up to what hydraulics discipline says. From one discipline to the next they do not have a concurrence of belief system.
@albyjoseph65973 жыл бұрын
@@amandadube156 🔥
@EmpyreanLightASMR2 жыл бұрын
3:44 on top of explaining the pitot tube REALLY well, I found this portion super hepful also. It visually shows, via the equation, why pressure drops as velocity goes up. Amazing. I love how all the profs say it's counterintuitive, and it is, but this makes is visually clear.
@brandonblair68685 жыл бұрын
First year aviation student....teacher today was explaining carburetor icing and when she got to the point where she said that the restricted portion of travel has less pressure that the large volume behind it, my brain checked out. This didn't make any sense to me on a common sense level. This video explains whats actually going on very well. Thanks
@EmpyreanLightASMR2 жыл бұрын
Are you a pilot now?
@josephrossman16005 жыл бұрын
"THAT'S GOTTA LOTTA PRESSURE" I lost it when he said that, it reminded me of Phill Swift in the flex seal commercials.
@VlogsByMeSL9 ай бұрын
Who else watching this video in 2024?
@jimmaskell31995 жыл бұрын
Thank you so much! Hard to find videos like this that actually interesting!
@rubensneto17624 жыл бұрын
Excellent explanation, thanks a lot. I'm studying about aircrafts systems and this video helped me a lot.
@nancything34898 жыл бұрын
Did David Cross just teach me fluid dynamics?
@caseybahrabadi218511 ай бұрын
Great job explaining Bernalillo equation. Thanks
@FirstDagger4 жыл бұрын
5:40 But isn't air compressible? Edit: Nevermind, seems that for speeds below Mach 0.3 air is treated as an in-compressible fluid.
@Observ45er3 жыл бұрын
Yes, you got it.
@alans1729 ай бұрын
Yes, but that's not true. The compressibility of air has nothing to do with its speed! The density of air is dependent on it's temperature. The
@tristansantacatterina85189 жыл бұрын
thanks from belgium
@GenericUsername13884 жыл бұрын
Hey! I'm studying to become a pilot and struggled to understand this now I know🙃 thanks
@ramiayyash39044 жыл бұрын
Excellent presentation. Very amusing all the way through. Thank you
@ianinvan6 жыл бұрын
Wow! Physics simplified ... I didn't know that was possible!
@edward111314 жыл бұрын
In the second example, wouldn't the density at point 2 be larger than that at point 1 as the presure is larger and air is compressible. Thanks.
@Observ45er3 жыл бұрын
Not at common speeds. Below about Mach 0.3 it is pretty much not compressed enough to make any difference.
@alans1729 ай бұрын
YES, YES, YES, and that's why Bernoulli's equations only apply to liquids, not gases.
@christophersmith80146 жыл бұрын
The lower pressure is observed due to the differential pressure between the inlet side of the pipe versus the outlet side. So the low pressure zone is in the expanding area of the discharge side of the constriction. The inlet side of the constriction should have increased pressure along the walls of the taper moving into the constricting zone. This effect can only be observed in a pressurized system so it's important to think of the system as a whole. Pressurized fluids will only move to a zone of lower pressure (when they aren't actively being compressed obviously) The zone of low pressure is often the open air. When the supplying force of the pressure encounters a restriction the overall pressure on the service side will be higher than if it were unrestricted. If the system is closed the overall pressure is at it's highest. If you open a valve the low pressure zone of the open atmosphere (or other lower pressure region of the system) will cause the contents of the system to flow and the pressure in the system as a whole will decrease. When you start to close the valve you constrict the flow rate and the pressure increases on the supply side as the valve closes. Fluid moves faster in the constriction because it is the first point of access to the low pressure on the outside of the system. The zone of restriction sets the flow rate for the material behind it. The material behind the constriction is a larger volume of material being dragged through a small hole, so naturally the cross-sectional area of the pool of material won't be progressing along the horizontal axis as fast as that of the restricted area. A good illustration of the speed and pressure differential is an hourglass flowing. Although it doesn't directly apply unless you consider gravitational pull to be the same as a zone of low pressure, and gravity seems to be the opposite of that; even though sometimes it's functionally the same.
@christiannebiggane37676 жыл бұрын
SO HELPFUL!! Thank you so much. Lightbulb moment.
@yaya34175 жыл бұрын
Useful for medical biophysics!! Thanks a lot
@thefenerbahcesk41565 жыл бұрын
medical biophysics? never heard of it. sounds cool.
@HolyRamanRajya2 жыл бұрын
Taking the analogy of conventional electricity in wire, is low pressure the cause or the effect of high velocity here?
@Bulgdoom9 жыл бұрын
Very good explanation, I never really understood the Venturi how pressure would go down in a constricted space, i mean when you think about oil pressure in a car's engine, its because of the small holes oil has to pass through (constrictions) to create a higher pressure to lubricate the parts.
@workhardplayhard8012 жыл бұрын
Eye of a hurricane or the like , is the 1st thing that came to mind. 🤔 seems like these tie together.
@joaop.b.figueiredo37692 жыл бұрын
Great explanation, thank you so much for the video!
@lisamariaschmid60447 жыл бұрын
Perfectly explained! Thanks :)
@Abdulaziz0Ghamdi5 жыл бұрын
It is very clear explanation ,, i really enjoyed it Good job dude
@jinyeliu56916 жыл бұрын
2:06 why do we care? well, i can answer that for you uhhh i wanna be a doctor!
@charlesleclerc47984 жыл бұрын
Doctor yet?
@charlesleclerc47984 жыл бұрын
@@jonathanstevenson8948 nah bro being a ferrari fan gave me tuberculosis im on my death bed right now
@enbinzheng-line Жыл бұрын
Will the air in the upward hole on the pitot tube not be sucked out? Because air has viscosity. The air flowing horizontally carries away the air inside the horizontal hole due to its viscosity.
@bnl1852 Жыл бұрын
But how can we use Bernoulli's equation on air if air is compressible? Density of air can change
@alans1729 ай бұрын
Correct. The density of a gas is dependent on its pressure and temperature. Bernoulli's equations relate to LIQUIDS, not gases!
@MrKikosko6 жыл бұрын
And the perpendicular intake is used for determining height of the plane, right? Because there is an atmospheric pressure in that second chamber, which equals P=P0*exp((-mgh)/RT).
@Da-Creams6 жыл бұрын
Za ck they have other static ports for height
@bg819734 жыл бұрын
Its not the added speed that decreases pressure, but the lesser volume. Two streams of equal volume but different speeds will have more pressure on the higher speed stream. When the pipe is reduced by, say half, the volume at any given point is half but flowing twice as fast. Its like the difference in a high velocity, low mass bullet and a low velocity, high mass bullet. The one with higher mass requires greater energy to stop and therefore has greater force, if we assume exactly half velocity and half mass. So in the half inch pipe, there is half as much surface area of water as in the one inch. Just like a hydraulic jack in reverse. The stream in the small cylinder travels further in proportion to the large one and with a proportional fraction of pressure. Ten pounds in and one hundred out. Reverse: one hundred pounds in, ten out but going ten times the distance.
@Observ45er3 жыл бұрын
+bg81973 What you refer to is the dynamic pressure of a faster stream being higher. This is the pressure you see when that stream comes up against a surface that stops it. It is hitting the surface, thus pushing more in the forward direction. . The pressures in a venturi talked about here are the static pressures. This is the pressure you would feel if you were traveling along with the fluid and it is not hitting you. This is the pressure felt on the sides of the pipe. . Also, a slower, but higher mass bullet can have the very same energy as a faster, lower mass bullet. So your analogy is also incorrect. The momentum is mv - Mass times velocity. .. Your hydraulics analogy is also incorrect. Hydraulics is a static based system of pressures. The idea is that the pressure is the SAME throughout. It is the FORCE that then varies with area. Force equals pressure times area. Smaller area less force - Larger area, more force.
@lajn12553 жыл бұрын
Excellent explanation! Thanks 👍
@physicsconceptsbytusharkha76384 жыл бұрын
In pitot tube how the velocity of the particle in contact with the wall becomes zero. Initially it had some velocity. So in a long run the point at wall will be accumulated with large number of such zero velocity particles. How do u pls explain this.
@jamesmasonic10 жыл бұрын
if the fluid is also the air, and if the velocity of the fluid is zero, can we then say that the static pressure is equal to the atmospheric pressure?
@69juggler699 жыл бұрын
+jamesmasonic Yes. Just need to consider the flying altitude and adjust both density and pressure.
@jaybabcock91236 жыл бұрын
So i get the point of the bottom tube, because you would get a pressure build up. But why does the top tube have a hole at 90 degrees to the air flow? What is the top tube measuring?
@jameslawton45348 жыл бұрын
Is there any way you could do a video on a pitot tube that uses a mercury manometer?
@danielshin24704 жыл бұрын
can someone please help me with a question... When comparing the velocity of blood flow through the arteries vs. the capillaries, according to the continuity equation, the velocity of blood is higher in the artery because the area of the artery is smaller than the net area of the capillaries. Then according to the venturi effect, the pressure should be the lowest at the artery, because it has higher velocity than the capillaries, but this is not the case. The blood pressure is the highest at the aorta in systemic circulation, can someone please explain why this is the case?
@jinyanzhou61066 жыл бұрын
Does it mean that when fluids went through the narrow portion, reach the other side, the pressure will increase again?
@Zoe-yu1io2 жыл бұрын
Yes. 😊
@JeremyRomayes7 жыл бұрын
best explanation, didnt put me to sleep unlike my prof
@automatonnation3025 жыл бұрын
Is pressure directly proportional to temperature ? If you use air instead of water would the smaller tube get colder ? Does the angle of funnel tubes make a difference ?
@lliaolsen7285 жыл бұрын
Yes the air can get much colder. Look up the effect of "Carburetor Icing". While it can cool air it's also a restriction. so if your next question is can you use this on an Automotive intake to cool air. I would say the gains would not outweigh the potential losses.
@vmars3165 жыл бұрын
@@lliaolsen728 Thanks Llia for your prompt reply !
@Tycy20142 жыл бұрын
Khana teaching me better then professor 365 days a year.
@marcel9117 жыл бұрын
So the output from the pitot tube ends up as the Air Speed indication inside the cockpit?
@krishnabharihoke31838 жыл бұрын
This is really helpful, thanks a lot!
@julianmele8 жыл бұрын
good explanation. Thank you so much!
@abrahamhamadi28045 ай бұрын
What about P=F/A, low area means high pressure?
@bg819734 жыл бұрын
I think you're missing the fact that the venturi tube and pitot tube, both work on a drop in atmospheric pressure. There is no "stagnant" air in the tube. It is at that point that pressure is reduced the most because there is no air and no atmospheric pressure. Thus, atmospheric pressure acting on anything attached, being about 15 pounds per square inch, will force it into this space. Likewise, the stagnation in the pitot tube is not by volume but a combination of pressure in the lower chamber and vacuum in the upper. This vacuum is the result of drop in atmospheric pressure as the air crosses over the opening and sucks the air out.
@Observ45er3 жыл бұрын
This is poorly worded, so it is impossible to tell what you are trying to say, but the first sentence is incorrect. I suspect you are confused about how the pitot tube works. One port of a pitot tube has stagnant air, the forward facing one which has a pressure that is higher than atmospheric pressure and is called stagnation pressure". Air is being rammed into it, thus increasing the pressure. Air is NOT sucked out" of the static port of a pitot tube; that port is at the surrounding, unchanged atmospheric pressure called 'static pressure'.. Therefore, the pitot tube operates via the increased pressure of the forward facing port (which is stagnation pressure) vs the surrounding atmospheric pressure in the static port on the side.
@awadelrahman9 жыл бұрын
Perfect Illustration
@2009duets8 жыл бұрын
hi i am studying for my red seal boilermaker exam and do not understand how to work out the answer so i was wondering if you can help Calculate the differential pressure developed by an open venturi tube measuring air speed at 50 MPH,at sea level (ρair = 0.00235 slugs/ft3), where the throat diameter is one-half that of the entrance diameter:∆P50 MPHairAlso, how much pressure will the venturi tube develop at twice the air speed (100 MPH)?
@rohitashwin91676 жыл бұрын
lisa N michael fleming wtf is slugs
@reypolice52313 жыл бұрын
@ 6:39 minutes/ seconds: you claim stagnation at center. Was this ever tested by a smoke test showing the smoke flow of all areas you mentioned. Whenever I've done such a smoke test it shows the air flowing up or down with a stagnation point at the wall sometimes in the form of a vortex spinning around at the wall only. The rest of the air you're claiming is stagnant gets drawn up the wall,by the slipstream of the air above and the air below which drags your so-called stagnant air up or down. You can test this for yourself by simply putting a fan in front of the wall and running smoke through your apparatus to test where the air actually goes.
@Mrsalirazatoor6 жыл бұрын
Thanku for explaining 🙃
@gagangayari59815 жыл бұрын
In the pitot tube ,does the air enters in the top chamber?
@12988Jake8 жыл бұрын
But isn't the water at higher pressure in the constricted part? Hence pressure washers producing more power from and pressure from a smaller nozzle than a larger one?
@dielaughing738 жыл бұрын
No, on this case increased velocity means decreased pressure. Conservaton of energy explains that. The pressure washer gives a high _velocity_ of water out of a small nozzle for exactly the same reason, going from (relatively) high pressure in the hose to low (atmospheric) pressure as it leaves the nozzle. It is the pressure of the water that converts to kinetic energy as the pressure drops suddenly (see the concept of PV work).
@YazinS7 жыл бұрын
Awesome vid, best explanation I've seen on this topic!
@MayLoft3 жыл бұрын
Thank you so much for explaining this.
@charlesferdinand4229 жыл бұрын
What software did you use to make this video?
@YazinS7 жыл бұрын
that looks like MS Paint!
@bascelik914 жыл бұрын
Amazing, thanks!
@aksh23767 жыл бұрын
You save my life
@naseemahmed70269 жыл бұрын
In the last part, to workout the Velocity from Pitot tube, how would we find out P1??
@Димитър-х4ш4 жыл бұрын
i think its too late to answer :D ,but P1 is atmospheric pressure!
@lethabojulius25444 жыл бұрын
nice explanation
@vadkaa50533 жыл бұрын
The thing is that you cant use Bernoulli's equation for Air!! It is not incompressible!!!!
@alans1729 ай бұрын
How can we spread the news when even NASA spruiks the same nonsense?
@aqibraja75647 жыл бұрын
how can we measure the pressure p1 why are we equating this pressure to static pressure?
@ravikoundinyavvp42527 жыл бұрын
we cant measure static pressure, or p1. but we can measure the difference in those pressures, because of the membrane separating them. (Think of the membrane like a spring, the more the elongation, the more the more the force, so more the pressure, in this case the pressure difference) i guess we can measure the pressure difference, with the elongation of that membrane, there must be some formula relating the elongation of the membrane to the pressure.
@thefenerbahcesk41565 жыл бұрын
Any brothers here from that mcat question about the venturi mask?
@sheharyarahmad70789 жыл бұрын
Great one
@nimanthadilz7 жыл бұрын
what happens if the pitot tube is directed opposite direction of the aeroplane flies?
@fatenhappy16 жыл бұрын
Great stuff ...
@naveedsyed29172 жыл бұрын
This guy is so much better than Sal.
@ahmetalitezcan62685 жыл бұрын
Well, then how do we know how much is the stagnation pressure?
@nocheechs5 жыл бұрын
6:49
@matarloum28949 жыл бұрын
Great video
@KokoMechE4 жыл бұрын
Dankieee😩
@cellls3 жыл бұрын
really coooooooooooool!
@aggabus4 жыл бұрын
had me at good day ..lost me at p1
@rushyahr77677 жыл бұрын
how come high velocity gases exhibit this behavior?
@testtest6483 жыл бұрын
The way you write the letter P is absolutely ubsurd
@Supernova-2176 жыл бұрын
why is the height ignored? there's such a big difference :/
@psndsh6 жыл бұрын
Thank you :)
@arwaabougharib86988 жыл бұрын
Thank you so much :)
@KokoMechE4 жыл бұрын
Means thanks.😁
@trevonholder34028 жыл бұрын
thanks man
@yazidnaufal99437 жыл бұрын
perfect, got exam in 2 hour and confused with books
@007ETA734 жыл бұрын
Love this guy lol
@rushyahr77677 жыл бұрын
lol, ok, I watched the rest of it, you just explained how a bulgarian 4 piece flash suppressor/ booster works
@aggabus4 жыл бұрын
nice
@ayush16435 жыл бұрын
Is this for iit jee
@througheagleseye5855 жыл бұрын
I wish physics would be applied to road traffic..
@lliaolsen7285 жыл бұрын
If the people acted as one unit it just might. However people are a-holes and follow too close or stop others from merging so it gradually slows the process to a halt. On a freeway or Highway. The fast lane ( Left lane(s) in the US) is considered the cross section or center line of the venturi. The onramps and offramps are the dimensional changes from 8 lanes to 4, the first two of the four lanes closest to the divider barrier are still the center of the venturi, call them lane 1 and 2. To decrease the pressure the cars in lanes 1 and 2 would have to increase speed from 50mph to 70mph leaving greater spaces for cars to merger between them at high speeds. The cars merging from the 7th and 8th lane onramps would have to speed up from 30mph to 70mph and make the same adjustments to increase following distance as they move from the outer most lanes approaching lanes 1 and 2, thus maintaining high speed at lower pressure.
@througheagleseye5855 жыл бұрын
.. there is also a 3 main rules making traffic flow as in venturi. 1. Speed has priority. 2. Passing happens only from left. 3. Slower moves to the right.
@BullseyeBenR2 жыл бұрын
The pressure is referring to the outside pressure! Speed increases moving from high to low outside force
@dominiccollins9951 Жыл бұрын
The equation is the explanation not the cause
@jamesdavis50963 жыл бұрын
or light! we have already done it
@wissalzaher48684 жыл бұрын
I love you.
@marcrogue52686 жыл бұрын
I find amusing when people teach and use statements such as this happens due to the Bernoulli equations or such natural process obeys such equation, utter nonsense. Thing don’t follow equations equations describe what is happening. But if you said the process is obeying the underlying physics that would be a better answer
@Curiousarawr8 жыл бұрын
itsa a gotsta staysa the samea!
@GixxerJake2 жыл бұрын
Motorcycle performance exhaust systems
@Paul-kd3ui Жыл бұрын
Add toogi colors
@AnChY94984 жыл бұрын
Хвала брт.
@XiD04 жыл бұрын
wow, so a pressure washer is a low pressure washer
@Observ45er3 жыл бұрын
Nope! The pressure of a high speed stream is using the DYNAMIC pressure. This is the pressure of the high speed stream hitting something that stops it. That fast stream of water actually has a static pressure that is atmospheric pressure - the same pressure as the air it is pushed into by the HIGH pressure inside the tank and hose. One needs to understand the difference between static and dynamic pressure.
@janrolandsson2566 жыл бұрын
i fell a sleep after 8 mins
@johnqpublic27184 жыл бұрын
Rho the Greek letter is not drawn like a p. Think łłłłłłłłłľľľľľłłłłłł
@harrickvharrick39575 жыл бұрын
He doesn't make much sense. If the water can't flow through the restricted / narrowed section 'on a higher speed' , the flow elsewhere in the pipe will simply slow down, his explanation suggests things on the forehand we don't know. The tap is a similar restriction / narrow spot in you water line, and it DOES slow down the water in all the rest of the tube / pipe, whatever you want to call it.
@Observ45er3 жыл бұрын
This is very disappointing to hear from the Kahn Academy. The reduced pressure is NOT "due to the equation".!!. The in crease in speed (acceleration) is DUE TO THE PRESSURE GRADIENT!
@IntelligentElephant5 жыл бұрын
This was not an excellent explanation. It was boring and not easily grasped, though everything you said was easily understandable. This video should show many real world examples/pictures/videos of venturi meter, with the "Madden highlight pen"