Bernoulli's Principle Demo: Paper on Table
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- Опубліковано 22 сер 2024
- This is a demonstration of Bernoulli's principle using a piece of paper taped to the edge of a table. Horizontal airflow over the paper raises it up.
This demonstration was created at Utah State University by Professor Boyd F. Edwards, assisted by James Coburn (demonstration specialist), David Evans (videography), and Rebecca Whitney (closed captions), with support from Jan Sojka, Physics Department Head, and Robert Wagner, Executive Vice Provost and Dean of Academic and Instructional Services.
I'm sorry to have to correct you! This is not a demo of Bernoulli's principle. Bernoulli's equation only applies along a streamline. This is a demonstration of the Coanda effect.
I'm glad someone said it. Bernoulli's principle doesn't mean a free jet is at lower pressure than atmospheric since that's not really possible to achieve with any subsonic piping system. Exit boundary conditions are a thing
Very simple example
But deep knowledge
And WRONG!
.
The common misconception is that any moving air, such as from a hair dryer, leaf blower or your mouth, has a lower static pressure than the stationary air around it. This is not true and comes from a misreading of Bernoulli’s Principle and misunderstanding of how to apply it. There are several demonstrations that are misinterpreted to show the static pressure is lower.
The moving stream of air from one of these is at the very same static, atmospheric pressure as the still air around it. It is NOT lower.
Here is the correct explanation.
This moving air has MORE total energy than the still air around it, not the same amount. This additional energy was added by the blower. The Total energy is the potential energy of the atmospheric pressure plus the kinetic energy of its motion or momentum.
Each of these ‘blowers’ adds energy to the air in the form of static pressure. This internal pressure is higher than the atmospheric pressure outside it.
For example, muscles move the diaphragm to squeeze the lungs. This increases pressure in the lungs.
This internal pressure pushes more on the air than the pressure outside
A pressure difference between two locations is called a Pressure Gradient. This reflects the idea that the pressure changes gradually between the two locations.
Because the internal pressure pushes more on the air, there is a net force toward the lower pressure outside the blower. The air is free to move and is accelerated toward the lower pressure. This is Newton’s Laws in fluids.
Air has mass. A Pressure Gradient provides a net force. Mass is accelerated away from the higher force, toward the lower force and gains speed in this case. This happens at the outlet of the blower and we have the stream of air starting internally at the higher pressure and accelerating to atmospheric pressure.
That’s it.
For those watching the conservation of energy rules, the TOTAL energy of air INSIDE the blower is the same as the TOTAL energy of the stream OUTSIDE the blower. The trip from inside to outside has no energy changes in that air.
We see that inside the lungs, all the air has nothing but potential energy in the form of static pressure and no motion with kinetic energy - no dynamic pressure. All the energy in the lungs is in the potential energy of static pressure.
The air gains speed (acceleration) as it exits, thus changing the extra potential energy of pressure into kinetic energy of the moving momentum of the air’s mass.
Great Video! really clear and helped me learn.Thank you!
The air out of the hose IS NOT at a lower pressure. NO NO NO. It is due to the *CURVEED* flow.
.
The common misconception is that any moving air, such as from a hair dryer, leaf blower or your mouth, has a lower static pressure than the stationary air around it. This is not true and comes from a misreading of Bernoulli’s Principle and misunderstanding of how to apply it. There are several demonstrations that are misinterpreted to show the static pressure is lower.
The moving stream of air from one of these is at the very same static, atmospheric pressure as the still air around it. It is NOT lower.
Here is the correct explanation.
This moving air has MORE total energy than the still air around it, not the same amount. This additional energy was added by the blower. The Total energy is the potential energy of the atmospheric pressure plus the kinetic energy of its motion or momentum.
Each of these ‘blowers’ adds energy to the air in the form of static pressure. This internal pressure is higher than the atmospheric pressure outside it.
For example, muscles move the diaphragm to squeeze the lungs. This increases pressure in the lungs.
This internal pressure pushes more on the air than the pressure outside
A pressure difference between two locations is called a Pressure Gradient. This reflects the idea that the pressure changes gradually between the two locations.
Because the internal pressure pushes more on the air, there is a net force toward the lower pressure outside the blower. The air is free to move and is accelerated toward the lower pressure. This is Newton’s Laws in fluids.
Air has mass. A Pressure Gradient provides a net force. Mass is accelerated away from the higher force, toward the lower force and gains speed in this case. This happens at the outlet of the blower and we have the stream of air starting internally at the higher pressure and accelerating to atmospheric pressure.
That’s it.
For those watching the conservation of energy rules, the TOTAL energy of air INSIDE the blower is the same as the TOTAL energy of the stream OUTSIDE the blower. The trip from inside to outside has no energy changes in that air.
We see that inside the lungs, all the air has nothing but potential energy in the form of static pressure and no motion with kinetic energy - no dynamic pressure. All the energy in the lungs is in the potential energy of static pressure.
The air gains speed (acceleration) as it exits, thus changing the extra potential energy of pressure into kinetic energy of the moving momentum of the air’s mass.
It helped me pass my test
This is amazing because it's contrary to what I'd imagine would actually happen. Science is interesting
Coandă effect no Benoulli
this will really help
If you want to be wrong.
..
The common misconception is that any moving air, such as from a hair dryer, leaf blower or your mouth, has a lower static pressure than the stationary air around it. This is not true and comes from a misreading of Bernoulli’s Principle and misunderstanding of how to apply it. There are several demonstrations that are misinterpreted to show the static pressure is lower.
The moving stream of air from one of these is at the very same static, atmospheric pressure as the still air around it. It is NOT lower.
Here is the correct explanation.
This moving air has MORE total energy than the still air around it, not the same amount. This additional energy was added by the blower. The Total energy is the potential energy of the atmospheric pressure plus the kinetic energy of its motion or momentum.
Each of these ‘blowers’ adds energy to the air in the form of static pressure. This internal pressure is higher than the atmospheric pressure outside it.
For example, muscles move the diaphragm to squeeze the lungs. This increases pressure in the lungs.
This internal pressure pushes more on the air than the pressure outside
A pressure difference between two locations is called a Pressure Gradient. This reflects the idea that the pressure changes gradually between the two locations.
Because the internal pressure pushes more on the air, there is a net force toward the lower pressure outside the blower. The air is free to move and is accelerated toward the lower pressure. This is Newton’s Laws in fluids.
Air has mass. A Pressure Gradient provides a net force. Mass is accelerated away from the higher force, toward the lower force and gains speed in this case. This happens at the outlet of the blower and we have the stream of air starting internally at the higher pressure and accelerating to atmospheric pressure.
That’s it.
For those watching the conservation of energy rules, the TOTAL energy of air INSIDE the blower is the same as the TOTAL energy of the stream OUTSIDE the blower. The trip from inside to outside has no energy changes in that air.
We see that inside the lungs, all the air has nothing but potential energy in the form of static pressure and no motion with kinetic energy - no dynamic pressure. All the energy in the lungs is in the potential energy of static pressure.
The air gains speed (acceleration) as it exits, thus changing the extra potential energy of pressure into kinetic energy of the moving momentum of the air’s mass.
Thanks
I have a question in regards to this phenomenon. In a Pitot tube, there are two holes. One hole in the front pointed into the airstream that captures the static + dynamic pressure.(stagnation pressure). The second hole is along the body of the tube perpendicular to the airstream. This second hole captures the static pressure. The static pressure is then "subtracted" from the stagnation pressure to leave just the dynamic pressure from which airspeed can be calculated. The airflow across the second hole is at the speed of the fluid so the pressure at this hole should be reduced by Bernoulli's equation below static pressure (?). Why doesn't this effect the results of the calculations?
shut up
NO! I am sorry this is a year old, but. . . .
..
Speed of air along a straight surface is NOT LOWER. Bernoulli says NOTHIONG about speed relative to a surface. NO. This is called a "static port" because it measures the STATIC pressure!
..
The pressure of a flow of air along a FLAT surface is atmospheric pressure! .
This "fast air has a lower pressure" thing is a BIG misunderstanding repeated over and over.
.
For this video:
When the paper is bent, this is Coanda because the jet of air is trying to go straight and also entraining air around it thus lowering the pressure lifting the paper. The paper prevents the entrainment, therefore the jet pulls on the paper trying to drag it along(Coanda saw this) - viscosity.
.
When the paper is straight, it is purely entrainment pulling the paper straight. It's like friction.
.
The air out of the hose IS AT atmospheric pressure, not below it!
.
Bernoulli occurs in the blower where higher pressure INSIDE pushes more than the outside atmospheric pressure, thus accelerating the air out into the lower atmospheric pressure. This is Newton. The in-out difference in pressure is the source of the force Accelerates the air out into the lower atmosphere.
..
..
Here's the rest of the correct story:
First, VERY Important thing to remember:
Air HAS MASS! Pressure on the outer part of a curve will always be higher because the fluid wants to go straight!
This ALSO makes the pressure less in the inside of a curve.
Try these:
*Understanding Lift Correctly: **rxesywwbdscllwpn.quora.com/*
*Understanding Bernoulli Correctly: **kyuoyckftflurrpq.quora.com/*
*Flow along a Convex Surface: **ua-cam.com/video/3MSqbnbKDmM/v-deo.html*
Great sir thank you
wao!👌👌👌
nice
Micheal Jackson? Seriously?!
From physics wallah student❤❤
Why is Physics so hell interesting?
And he is WRONG!
The common misconception is that any moving air, such as from a hair dryer, leaf blower or your mouth, has a lower static pressure than the stationary air around it. This is not true and comes from a misreading of Bernoulli’s Principle and misunderstanding of how to apply it. There are several demonstrations that are misinterpreted to show the static pressure is lower.
The moving stream of air from one of these is at the very same static, atmospheric pressure as the still air around it. It is NOT lower.
Here is the correct explanation.
This moving air has MORE total energy than the still air around it, not the same amount. This additional energy was added by the blower. The Total energy is the potential energy of the atmospheric pressure plus the kinetic energy of its motion or momentum.
Each of these ‘blowers’ adds energy to the air in the form of static pressure. This internal pressure is higher than the atmospheric pressure outside it.
For example, muscles move the diaphragm to squeeze the lungs. This increases pressure in the lungs.
This internal pressure pushes more on the air than the pressure outside
A pressure difference between two locations is called a Pressure Gradient. This reflects the idea that the pressure changes gradually between the two locations.
Because the internal pressure pushes more on the air, there is a net force toward the lower pressure outside the blower. The air is free to move and is accelerated toward the lower pressure. This is Newton’s Laws in fluids.
Air has mass. A Pressure Gradient provides a net force. Mass is accelerated away from the higher force, toward the lower force and gains speed in this case. This happens at the outlet of the blower and we have the stream of air starting internally at the higher pressure and accelerating to atmospheric pressure.
That’s it.
For those watching the conservation of energy rules, the TOTAL energy of air INSIDE the blower is the same as the TOTAL energy of the stream OUTSIDE the blower. The trip from inside to outside has no energy changes in that air.
We see that inside the lungs, all the air has nothing but potential energy in the form of static pressure and no motion with kinetic energy - no dynamic pressure. All the energy in the lungs is in the potential energy of static pressure.
The air gains speed (acceleration) as it exits, thus changing the extra potential energy of pressure into kinetic energy of the moving momentum of the air’s mass.
l guess this is okay
Your icon isn’t, change it
this is so boring
When you realize that an F1 car can generate 1,5 Tons of downforce and withstands 4 Gs while turning thanks to this principle, that's not so boring 😉
@@davep1474 hey you! no one cares nerd
@@davep1474 BOOOOO!
@@davep1474 *II HATE YOU!
@@davep1474 its still boring. Who the hell thinks that thats interesting?