Michel, your video series is excellent. haven't had to do any math like this for decades, so going slowly through all of the substitutions in the formulas makes each topic very easy to understand. Thank you.
when fluid is going from point 4 to point 5 I can clearly see why elevation head is lost and so pressure goes up, but what I have never understood is how do we account for the fact that the fluid should be accelerating because of gravity through the downslope segment? If it's accelerating it would seem to violate the continuity equation for steady flow and there'd be no conservation of mass. So what is actually happening when confined flow in a pipe goes downhill? In the case of a stream of water is free fall the water stream itself will taper because it is accelerating by gravity, so in order to maintain conservation of mass along the stream the diameter shrinks, but I don't think anything like that is going on here. So what is the answer?
There are two things that can happen. The fluid can gain speed or the pressure can increase. The speed of the fluid can only change if the diameter of the pipe changes, therefore the pressure must increase with decreasing height if the diameter of the pipe remains the same.
Hi Michel Van. Very good videos. Simple and easy. I follow all of them. Can you please do something on Heat Losses and Evaporation rates for swimming pools. Regds, Jim
Dear Michael, I love your lectures thaks for your effort. You got a little mistake. Pressure along pipe always decrease, on the contrary the flow goes backwards. Velocity varies and energy is reduced inexorably. Higher Pressure in a flowing fliud goes from P1 upstream to loer Pressure P2 downstream always, P1> P2. Cheers
There is no error in the video, however this is just an academic example. In the real world of fluids flowing through pipes, the pressure will decrease as you move along the flow and energy will be lost due to friction and the viscosity of the fluid.
@@MichelvanBiezen Thanks Michael for your response, very kind. I completely trust in your experience as lecturer, probably it is better to use mass as a conservation law or any other example for energy conservation. Bernoulli equation requires a friction loss term to be consistent. In any condition the pressure downstream won’t be higher thus this concept is wholly erroneous for the student. The consequence of a wrong concept maybe catastrophic for anyone.
Dear Micheal of course that's completely wrong. Pressure must be always higher upstream. It's equivalent to sustain that objects fall upwards. If you keep sustaining this you better go back to your university. Not bad for you to refresh basics. Cheers
@@MichelvanBiezen yes, I'm so thankful for your channel. I will be watching every thermo/fluid dynamic topic until my final test in July. HSLU in Switzerland
Trying to wrap my head around this. At point 3, surely the decreased diameter at point 4 has as much to do with the increase in pressure at point 3, right? Let's say that you cut off the rest of the pipe halfway along point 3 (so that the liquid was just spraying out into the open), would the pressure measured at that point (the lip of the pipe) still be higher than at point 2?
Excellent video!! Let me ask something that has troubling me now for a long. Let's pretend we have a pipe like the (4-5) section and the upper end is at the bottom of a tank full of fluid and the lower end end up in an empty tank.Now the water will start flowing into the pipe downfall.If we apply bernoulli's equation between two points of the pipe A(higher point) and B(lower point) then because the velocity doesnt change and the difference of the height is hA>hB,the difference of the pressure will be pB>pA. So the fluid flows from a point of low pressure to a point of high pressure.Is this right?because we know that this law goes the other way.Or when we say that the flow must be from higher to lower pressures we mean the total pressures? Thank you.
John, I had a hard time following your question. But this may help: There are 3 things that control the flow of water (or fluid) in a pipe. (Height, velocity, and pressure) Bernoulli figured out how these interplay, so that one could increase while the other decreases. So it is possible for water to flow from low pressure to high pressure, of from high pressure to low pressure as long as the other factors compensate for it.
What if you have 2 or 3 incoming and varying flow rates going to different pipes and meeting at one point? 1. A1V1 2. A2V2 3. A3V3 Is the total output flow rate (total AV) equal to = A1V1 + A2V2 + A3V3?
Yes, because the sum of the volumes per unit time flowing through each of the smaller pipes equals the volume per unit time flowing through the big pipe.
fenash1 You have to combine 2 equations: The first is Bernoulli's equation where you know that: P + rho*g*h + (1/2)*rho*v^2 = constant thus when one changes something else has to change. The second is the flow equation: A1v1 = A2v2 That must always be true as well. The combination of these 2 equations will give you the correct answer.
Assuming the fluids flowing to the right, does area (3) not push backwards onto area (2) and try to flow in the opposite direction(as it has greater pressure)? Seeing as we're going from an area of lower pressure to higher pressure. Don't you need a greater force on the left side than on the right to have a direction of flow? (to the right)
Bernoulli's equation is simply the realization that P + rho*g*h + (1/2)*rho*v^2 = constant for any point in the pipe. That allows us to find the pressure or velocity at any point in the pipe assuming we know the other parameters. Determining which direction the water will flow is a different problem with a different equation. Just like everything else in nature, water will flow from a higher potential energy to a lower potential energy, or simply, water will flow down hill.
Just coming out of Bernoulli's theorem , generally speaking : Pressure is something called force per unit area as we know. That means if area decreases, certainly pressure should increase. Then how is pressure at point #6 lower than point #5. Please explain!
Rahul Iyer Like every theory in physics, you must start with a premise that is correct. The statement: "if area decreases, pressure should increase" must be based on a an equation that you know is correct in this particular situation. Which equation did you start with in order to make that statement? (I am trying to show you how we should look physics in general, the answer will become apparent......)
Michel van Biezen Thankyou for your reply!But I am still confused over here.The pressure head in the Bernoulli's theorem is derived actually from the basic relation : Pressure = Force / Area as follows :P = F/A = Weight / Area = (weight density x Volume)/ Area = ((weight density x (area x depth))/ Area { Area in the numerator and denominator gets cancelled } = Weight density x depthTherefore,pressure head , i.e. depth = Pressure/weight densityComing back to the basic relation : P = F/AHere, P= pressure ; F= Normal force ; A = area of surface in contact.What I mean to say is that , area of contact at point#6 seems to be less than point#5 which will increase the value of P considerably.I don't know to what extent I am right. Please correct me if I am wrong.After this discussion I would be keen to know from you the relationship between pressure and flow rate in a water distribution network.Thanx & regards,Rahul Iyer
Rahul Iyer Now we are getting closer to understanding Bernoulli's equation. Pressure in a pipe is caused by 3 components, in your description above, you are only looking at 1 of the 3 components: pressure caused by the weight of the water above the point of consideration. The second component is caused by pressure at the end of the pipe, which can be caused by a number of things: the atmosphere, a pump, etc. The third component is the speed of the fluid through the pipe which decreases with increasing speed. When the pipe narrows, the speed increases and thus the pressure reduces in sections where the pipe is narrow.
sir, may i ask how do we know only one of the variables change, or 2 of the variable changes like if v increases, pressure decrease or if v increase, so is height increase, pressure will decrease?
We made a video that explains Bernoulli's equation and where it comes from. PHYSICS 34.2 BERNOULLI'S EQUATION EXPLAINED Physics: Fluid Dynamics: Fluid Flow (1.6 of 7) Bernoulli's Equation Derived th-cam.com/video/R5uoTadxhpU/w-d-xo.html
Hello Sir, I have two questions. 1. Why does pressure increase as velocity decrease? 2. Why pressure increase as height decrease? (No detailed answers required just hints) Thank you Sir.
1) When molecules are on the move, they create spaces between them and the interactive forces are somewhat damped due to the motion, and thus there will be less pressure. When molecules stop moving they settle in and pressure will go up. 2) Pressure in a fluid as a function of depth = density x g x h where h is the depth below the surface.
hi! thanks for the video. its very useful. i would like to see the effect from point1 to point3 (skipping point2). i mean simulataneous change in cross-section & height.
The tube at 7 is much tighter ? Thats the pressure going up first, the velocity going down, thus the flow rate going down because the section is smaller Q=S.V
Lets imagine the area of a small tube as a valve thats slightly open. If u have a valve and u close to the middle, u'll notice the flow rate reduced after. Thats a squeezed area, same concept for smaller section if u get my idea.
Mark, If you compare point # 6 to point # 5, the only thing that is changing is the width of the pipe (it becomes smaller going from 5 to 6). That means the velocity must increase going from 5 to 6. That means the pressure at 6 must be lower than the pressure at 5.
Since the diameter at 5 is the same as the diameter at 4, the velocity must be the same at 5 and at 4. Since h at 5 is lower than 4, the pressure at 5 must be higher. The pressure increase at 5 = rho * g * h where h is the height difference between 4 and 5.
Michel van Biezen thank you for your answer. and thank you for the video...they are helping me a lot. I did not take in consideration that this is a system closed where it is not opened to the atmosphere. But if we have an open system, the study will be different right? like a waterfall in a lake. because the velocity at the lake will be 0.
if we created a maximum possible heron's fountain in size,and it is powered by hydroelectric power dam then, will it restored the water going out, so we stored more energy
902hater Because the flow rate is constant. Therefore if the pipe is wider, more liquid is occupying a cross sectional area, the fluid must be moving slower in order for the same amount of liquid to pass a specific point in a specific time. Mathematically --> dV/dt = constant therefore Adx/dt = constant; dx/dt is velocity: so A1v1=A2v2 if A gets bigger velocity gets smaller.
sir like this maybe a dumb question so if the height is more the distance to be traveled by fluid increases and so time increases proportionally so force around the walls of the container with increase in time leads to increase in impulse therefore force increases proportionally so if force increases and area remains the same the pressure increases ...... idk pls help this was just a thought experiment
It has more to do with kinetic and potential energy. See this video in the playlist: Physics: Fluid Dynamics: Fluid Flow (1.6 of 7) Bernoulli's Equation Derived
+Tahsin Rahi If you go look at (2 of 7) it says when v slows down, pressure increase - also has the equation on the board while he's explaining. Makes it a little easier to understand it guess. Go have a look ^
That is the case in an enclosed container. With a fluid in motion inside a pipe, a change in the cross sectional area will change the speed of the fluid, which in turn will change the pressure in the fluid.
heron's fountain equation with graph, please discussed it with me to get the cheapest way of energy from atmospheric pressure forever for mankind's 😇😇😇😇😠😕😕😕😕
1st of all, thnx 4 posting these vids 2nd, u lost me at point 3 --- i mean im w u at point 2 cuz where the height of the pipe increases, the pressure has 2 decrease xcept at point 3 the circumference of the pipe increases so shouldnt the pressure decrease, in order 4 there 2 remain a constant? similarlly the pressure at point 4 should increase since the pipes circumference decreases, rite? i totally agree w the pressure goin up at point 5 cuz the elevation of the pipe went down but then shouldnt the pressure increase even mor at point 6 cuz the pipes circumference jus decreased? --- very much agree that as the pipe widens the velocity slows down but the pressure also decreases cuz velocity is predicated on the pressure like popping a zit 4 lack of a betta xample..the mor pressure at which u squeeze it, the higher the velocity of the white umm shiz subsequently if u decrease the pressure, the velocity decreases so the said white shiz wont make it 2 the mirror (yeah, no..gross but effective xample) --- im totally not tryin 2b a skoosh la doosh jus confused now is all
Michel van Biezen From point 2 to 3, since the fluid is going through the wider section of the piper (thus the radius is larger in size), the velocity is decreasing. The smaller the radius, the larger the velocity of the fluid. Since the velocity of the fluid is decreasing, the pressure must compensate the velocity of the fluid so it increases. We know they are inversely proportional. Correct? I just want to make sure i really do understand this.
***** Denny, In general you are correct. In isolation (ignoring all other aspects), if the velocity of a fluid increases the pressure decreases and if the velocity decreases, the pressure increases. What is always correct, : P + (1/2)*rho*v^2 + rho*g*h = constant.
I know it's been 8 years since this video, but I love your videos. You saved me in physics, ELE and now you're going to save me in fluids.
Glad to hear it. Keep it going.
This is surely the best example in this field. I gained a lot more understanding compared to just making calculations with formulas. Thanks!
Michel, your video series is excellent. haven't had to do any math like this for decades, so going slowly through all of the substitutions in the formulas makes each topic very easy to understand. Thank you.
This guy is legend.!!!!!!! I will surely donate a lot after I graduate and I believe these videos will guide me.
Best explanation of the relationships ever. It's almost like professors think explaining things simply is stupid or something.
You are one of the best presenters I have watched in TH-cam hood job well done congratulations
Thank you.
If the velocity goes up due to narrowing, the pressure gets down. This is so incredible and fascinating!
Coolest simplest smartest best explanation ... I have ever seen & learned.... Tq so much sir!
I wrote everything on your board. Im designing pipe network as university project. Thank you so much/kuwait
Oh yeah this the best example for understanding the concept...
U r awesome sir...
Very good that you teach about Bernoulli's equation
Glad you liked it. 🙂
when fluid is going from point 4 to point 5 I can clearly see why elevation head is lost and so pressure goes up, but what I have never understood is how do we account for the fact that the fluid should be accelerating because of gravity through the downslope segment? If it's accelerating it would seem to violate the continuity equation for steady flow and there'd be no conservation of mass. So what is actually happening when confined flow in a pipe goes downhill? In the case of a stream of water is free fall the water stream itself will taper because it is accelerating by gravity, so in order to maintain conservation of mass along the stream the diameter shrinks, but I don't think anything like that is going on here. So what is the answer?
There are two things that can happen. The fluid can gain speed or the pressure can increase. The speed of the fluid can only change if the diameter of the pipe changes, therefore the pressure must increase with decreasing height if the diameter of the pipe remains the same.
Amazing teaching skills and brilliant explanation sir
Hi Michel Van. Very good videos. Simple and easy. I follow all of them. Can you please do something on Heat Losses and Evaporation rates for swimming pools. Regds, Jim
That is an interesting question. We added it to the list of requests. Thank you. 🙂
Dear Michael, I love your lectures thaks for your effort. You got a little mistake. Pressure along pipe always decrease, on the contrary the flow goes backwards. Velocity varies and energy is reduced inexorably. Higher Pressure in a flowing fliud goes from P1 upstream to loer Pressure P2 downstream always, P1> P2. Cheers
There is no error in the video, however this is just an academic example. In the real world of fluids flowing through pipes, the pressure will decrease as you move along the flow and energy will be lost due to friction and the viscosity of the fluid.
@@MichelvanBiezen Thanks Michael for your response, very kind. I completely trust in your experience as lecturer, probably it is better to use mass as a conservation law or any other example for energy conservation. Bernoulli equation requires a friction loss term to be consistent. In any condition the pressure downstream won’t be higher thus this concept is wholly erroneous for the student. The consequence of a wrong concept maybe catastrophic for anyone.
There is nothing conceptually or mathematically incorrect about this example.
Dear Micheal of course that's completely wrong. Pressure must be always higher upstream. It's equivalent to sustain that objects fall upwards. If you keep sustaining this you better go back to your university. Not bad for you to refresh basics. Cheers
I wish my university would just explain it clearly as you do. It always feels they are hiding the simple explanation.
At least you can visit our channel when they don't explain it well. What university do you attend?
@@MichelvanBiezen yes, I'm so thankful for your channel. I will be watching every thermo/fluid dynamic topic until my final test in July.
HSLU in Switzerland
All the best with your studies and your final exam. 🙂
I wish you were my professor. Thank you much!!
Thank you so much,this is a good start.
Glad it was helpful!
Hello, could the Bernoulli equation be used only considering points 1 and 6, that is, ignoring the height changes along the rest of the flow?
That is correct. You can pair up any 2 points.
You are the man
This guy carries 258k engineers and physics students to pass the exam 🗿
Excellent explanation 👍
Trying to wrap my head around this.
At point 3, surely the decreased diameter at point 4 has as much to do with the increase in pressure at point 3, right?
Let's say that you cut off the rest of the pipe halfway along point 3 (so that the liquid was just spraying out into the open), would the pressure measured at that point (the lip of the pipe) still be higher than at point 2?
Excellent video!!
Let me ask something that has troubling me now for a long.
Let's pretend we have a pipe like the (4-5) section and the upper end is at the bottom of a tank full of fluid and the lower end end up in an empty tank.Now the water will start flowing into the pipe downfall.If we apply bernoulli's equation between two points of the pipe A(higher point) and B(lower point) then because the velocity doesnt change and the difference of the height is hA>hB,the difference of the pressure will be pB>pA.
So the fluid flows from a point of low pressure to a point of high pressure.Is this right?because we know that this law goes the other way.Or when we say that the flow must be from higher to lower pressures we mean the total pressures?
Thank you.
John,
I had a hard time following your question.
But this may help: There are 3 things that control the flow of water (or fluid) in a pipe. (Height, velocity, and pressure)
Bernoulli figured out how these interplay, so that one could increase while the other decreases. So it is possible for water to flow from low pressure to high pressure, of from high pressure to low pressure as long as the other factors compensate for it.
Thank you for the response,this helps me to get a better understanding.English is not my native language so im sorry for any mistakes.
Excellent idea to explain it.
What is elevation? at 1:22
The elevation is relative to a reference point. Point 1 would be a good reference point and thus point 2 would be h2 above h1.
2 . and yeah velocity will decrease since its inversely proportional to time is it that way i forgot to mention that
What if you have 2 or 3 incoming and varying flow rates going to different pipes and meeting at one point?
1. A1V1
2. A2V2
3. A3V3
Is the total output flow rate (total AV) equal to = A1V1 + A2V2 + A3V3?
Yes, because the sum of the volumes per unit time flowing through each of the smaller pipes equals the volume per unit time flowing through the big pipe.
Why only Pressure changes when height or velocity change and not for example when height goes down velocity changes?
fenash1
You have to combine 2 equations:
The first is Bernoulli's equation where you know that:
P + rho*g*h + (1/2)*rho*v^2 = constant thus when one changes something else has to change.
The second is the flow equation:
A1v1 = A2v2
That must always be true as well. The combination of these 2 equations will give you the correct answer.
+Michel van Biezen So if the radius of the pipe is the same in two sections, then the velocity will be the same as well, regardless of elevation?
How about when the pipe is bigger and has higher altitude relative to the previous point?
OMG!! you just saved my life thank you!!
I am sure it wasn't that dramatic, but I am glad it helped.
hahahah
Assuming the fluids flowing to the right, does area (3) not push backwards onto area (2) and try to flow in the opposite direction(as it has greater pressure)? Seeing as we're going from an area of lower pressure to higher pressure. Don't you need a greater force on the left side than on the right to have a direction of flow? (to the right)
Bernoulli's equation is simply the realization that P + rho*g*h + (1/2)*rho*v^2 = constant for any point in the pipe. That allows us to find the pressure or velocity at any point in the pipe assuming we know the other parameters. Determining which direction the water will flow is a different problem with a different equation. Just like everything else in nature, water will flow from a higher potential energy to a lower potential energy, or simply, water will flow down hill.
thank you so much for this video. made it very clear.
Just coming out of Bernoulli's theorem , generally speaking : Pressure is something called force per unit area as we know. That means if area decreases, certainly pressure should increase. Then how is pressure at point #6 lower than point #5. Please explain!
Rahul Iyer
Like every theory in physics, you must start with a premise that is correct.
The statement: "if area decreases, pressure should increase" must be based on a an equation that you know is correct in this particular situation.
Which equation did you start with in order to make that statement?
(I am trying to show you how we should look physics in general, the answer will become apparent......)
Michel van Biezen Thankyou for your reply!But I am still confused over here.The pressure head in the Bernoulli's theorem is derived actually from the basic relation : Pressure = Force / Area as follows :P = F/A = Weight / Area = (weight density x Volume)/ Area = ((weight density x (area x depth))/ Area { Area in the numerator and denominator gets cancelled } = Weight density x depthTherefore,pressure head , i.e. depth = Pressure/weight densityComing back to the basic relation : P = F/AHere, P= pressure ; F= Normal force ; A = area of surface in contact.What I mean to say is that , area of contact at point#6 seems to be less than point#5 which will increase the value of P considerably.I don't know to what extent I am right. Please correct me if I am wrong.After this discussion I would be keen to know from you the relationship between pressure and flow rate in a water distribution network.Thanx & regards,Rahul Iyer
Rahul Iyer
Now we are getting closer to understanding Bernoulli's equation.
Pressure in a pipe is caused by 3 components, in your description above, you are only looking at 1 of the 3 components: pressure caused by the weight of the water above the point of consideration.
The second component is caused by pressure at the end of the pipe, which can be caused by a number of things: the atmosphere, a pump, etc.
The third component is the speed of the fluid through the pipe which decreases with increasing speed. When the pipe narrows, the speed increases and thus the pressure reduces in sections where the pipe is narrow.
wow thank you Michel van Biezen for that explaination
sir, may i ask how do we know only one of the variables change, or 2 of the variable changes like if v increases, pressure decrease or if v increase, so is height increase, pressure will decrease?
We made a video that explains Bernoulli's equation and where it comes from. PHYSICS 34.2 BERNOULLI'S EQUATION EXPLAINED Physics: Fluid Dynamics: Fluid Flow (1.6 of 7) Bernoulli's Equation Derived th-cam.com/video/R5uoTadxhpU/w-d-xo.html
@@MichelvanBiezen thanks a lot sir, but may I ask another question, at part 4 , how do we know that the velocity doesn't change 🤔
Hello Sir,
I have two questions.
1. Why does pressure increase as velocity decrease?
2. Why pressure increase as height decrease? (No detailed answers required just hints)
Thank you Sir.
1) When molecules are on the move, they create spaces between them and the interactive forces are somewhat damped due to the motion, and thus there will be less pressure. When molecules stop moving they settle in and pressure will go up. 2) Pressure in a fluid as a function of depth = density x g x h where h is the depth below the surface.
At point 5 v decreases and so does h which makes p quite high. In point 6 h decreases a bit but v increases which makes it hard to tell?
The difference in height between 5 and 6 is supposed to be negligible. The faster speed at 6 is because the pipe is much more narrow at 6 than at 5.
hi! thanks for the video. its very useful. i would like to see the effect from point1 to point3 (skipping point2). i mean simulataneous change in cross-section & height.
Thank you so much! Amazing videos
Thank you for these videos.
The tube at 7 is much tighter ? Thats the pressure going up first, the velocity going down, thus the flow rate going down because the section is smaller Q=S.V
The flow rate is the same everywhere along the tube. Therefore in narrower sections the water flows faster and the pressure drops.
This is exactly my doubt, what makes you say the flow rate stays the same everywhere ? Why not both speed and section makes it flow lower.
Lets imagine the area of a small tube as a valve thats slightly open. If u have a valve and u close to the middle, u'll notice the flow rate reduced after. Thats a squeezed area, same concept for smaller section if u get my idea.
thanks for the intuition, really helpful
This is very useful for ap physics 2
I got a raw 100 for this topic on my fluid dynamics test and quiz. Thank you.
Also I got a 5 on the AP Physics 2 test. Thank you very much.
# 6 the pressure should go up. If put at psi gauge at the end of #6 and restriction psi should go up please explain thanks
Mark,
If you compare point # 6 to point # 5, the only thing that is changing is the width of the pipe (it becomes smaller going from 5 to 6).
That means the velocity must increase going from 5 to 6.
That means the pressure at 6 must be lower than the pressure at 5.
Thanks
So how would you compare point 1 to point 3
At point 5 , the pressure and the velocity should be increased, is it not?
Relative to what point?
to the number 4
Since the diameter at 5 is the same as the diameter at 4, the velocity must be the same at 5 and at 4. Since h at 5 is lower than 4, the pressure at 5 must be higher. The pressure increase at 5 = rho * g * h where h is the height difference between 4 and 5.
Michel van Biezen thank you for your answer. and thank you for the video...they are helping me a lot. I did not take in consideration that this is a system closed where it is not opened to the atmosphere. But if we have an open system, the study will be different right? like a waterfall in a lake. because the velocity at the lake will be 0.
u r the best thanx
if we created a maximum possible heron's fountain in size,and it is powered by hydroelectric power dam then, will it restored the water going out, so we stored more energy
reasonable , thx sir
Why does Velocity decrease when diameter increase and vice versa?
902hater Because the flow rate is constant. Therefore if the pipe is wider, more liquid is occupying a cross sectional area, the fluid must be moving slower in order for the same amount of liquid to pass a specific point in a specific time. Mathematically --> dV/dt = constant therefore Adx/dt = constant; dx/dt is velocity: so A1v1=A2v2 if A gets bigger velocity gets smaller.
sir like this maybe a dumb question so if the height is more the distance to be traveled by fluid increases and so time increases proportionally so force around the walls of the container with increase in time leads to increase in impulse therefore force increases proportionally so if force increases and area remains the same the pressure increases ...... idk pls help this was just a thought experiment
It has more to do with kinetic and potential energy. See this video in the playlist: Physics: Fluid Dynamics: Fluid Flow (1.6 of 7) Bernoulli's Equation Derived
@@MichelvanBiezen ok i will do
How velocity and pressure are related by formula?
The difference in pressure = (1/2) x density ( Vf^2 = Vo^2)
Warum ändert sich der Betriebsdruck?
The pressure can change for 2 reasons. 1) The pressure decreases with increasing height. 2) The pressure decreases with increasing velocity
Very clear!
as P = F/A ,if A increases, P decreases. But at point 3, u said P will increase. Why ?
+Tahsin Rahi At point 3 the velocity decreases, therefore the pressure increases
+Tahsin Rahi If you go look at (2 of 7) it says when v slows down, pressure increase - also has the equation on the board while he's explaining. Makes it a little easier to understand it guess. Go have a look ^
there's no relation between the velocity and the height ?
If the cross sectional area doesn't change then the velocity cannot change irrespective of the height.
where is the NO.18
Shouldn't a decrease in volume should increase the pressure? Because if you squeeze it then the atoms should hit the surface of the pipe more often.
That is the case in an enclosed container. With a fluid in motion inside a pipe, a change in the cross sectional area will change the speed of the fluid, which in turn will change the pressure in the fluid.
thank you very much, it's very helpful :)
Thanks sir..
you rock!
I would not have thought that pressure would increase by a decreasing velocity!? that doesnt make sence to me
Our "intuition" is often wrong. Better to stick to the equations that have been proven.
haha thank you!
Tnx sir
Sir when we have a 7.5 psi in suction pressure so can we calculate tahat pressure for finding discharge pressure
Is it always going to be true when Height increase, Pressure decrease. Vice Versa
and when Velocity increase, Pressure decrease. Vice Versa
visibility less
heron's fountain equation with graph, please discussed it with me to get the cheapest way of energy from atmospheric pressure forever for mankind's
😇😇😇😇😠😕😕😕😕
спосиба сир
1st of all, thnx 4 posting these vids
2nd, u lost me at point 3
---
i mean im w u at point 2 cuz where the height of the pipe increases, the pressure has 2 decrease
xcept at point 3 the circumference of the pipe increases so shouldnt the pressure decrease, in order 4 there 2 remain a constant?
similarlly the pressure at point 4 should increase since the pipes circumference decreases, rite?
i totally agree w the pressure goin up at point 5 cuz the elevation of the pipe went down
but then shouldnt the pressure increase even mor at point 6 cuz the pipes circumference jus decreased?
---
very much agree that as the pipe widens the velocity slows down but the pressure also decreases cuz velocity is predicated on the pressure
like popping a zit 4 lack of a betta xample..the mor pressure at which u squeeze it, the higher the velocity of the white umm shiz
subsequently if u decrease the pressure, the velocity decreases so the said white shiz wont make it 2 the mirror (yeah, no..gross but effective xample)
---
im totally not tryin 2b a skoosh la doosh jus confused now is all
Lance,
Going from point 2 to point 3, the velocity slows down;
A2v2 = A3v3
Therefore the pressure at point 3 must be higher than at point 2.
Michel van Biezen From point 2 to 3, since the fluid is going through the wider section of the piper (thus the radius is larger in size), the velocity is decreasing. The smaller the radius, the larger the velocity of the fluid. Since the velocity of the fluid is decreasing, the pressure must compensate the velocity of the fluid so it increases. We know they are inversely proportional. Correct? I just want to make sure i really do understand this.
***** Denny,
In general you are correct. In isolation (ignoring all other aspects), if the velocity of a fluid increases the pressure decreases and if the velocity decreases, the pressure increases.
What is always correct, : P + (1/2)*rho*v^2 + rho*g*h = constant.