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Diffrence between Static; Dynamic and Stagnation Pressure
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- เผยแพร่เมื่อ 15 พ.ค. 2017
- #fluidmechanics #fm #gate #gtu #mechanical #concepts #applications #static #dynamic #stagnation #pressure
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In this lecture, It is rigorously explained that how static, dynamic and stagnation pressures are different from each other and what is their physical significance. This is explained with some funny and real life example. You will love to watch this video.
Static Pressure: Pressure at a point in fluid is called static pressure
Stagnation pressure: Pressure that obtained by fluid if it brought to rest without loss of mechanical energy
Dynamic Pressure: Difference between stagnation and static pressure is called dynamic pressure. Which is because of the kinetic energy of particle.
![[Aero Fundamentals #6] Static Pressure, Dynamic Pressure, and Total Pressure Explained](http://i.ytimg.com/vi/F0HNjp5jGOI/mqdefault.jpg)
![[Aero Fundamentals #6] Static Pressure, Dynamic Pressure, and Total Pressure Explained](/img/tr.png)
The way you demonstrated this, reminds me about the technique which Prof Richard Feynnmen used to practice.It was an amazing demonstration.
Best explanation with the best example. 👌👍
You guys just saved my ass in my fluid mechanics lab report haha. Thank you for the video!
Enjoyed a lot and now I'm not confused anymore.
Dear sir, thank you very much. It was very simple.
thanks you , just a remark : the case of the diffuser & the convergent nozzle is true only when the flow is supersonic at the inlet. If the flow is subsonic : When A increases , V decreases et Pstat increases ; When A decreases , V increases et Pstat decreases
Yess!
Great video, although it was difficult to understand with the accent at times, but I guess there's nothing u can do about that. Maybe consider adding in subtitles for your future videos. Thanks again.
I loved to watch this video.
You explain it with more simplicity . Keep it up.. And thanks
This is very well explained !! Thank you so much !!
Good explanation sir thanks lot
How do we ensure that in case of stagnation pressure measurement, fluid is brought to rest isentropically?
cant thank you enough..... I have finally understood the concept.
very inspiring video.Keep on uploading new videos.All the best
In the video, it says that stagnation pressure at inlet and outlet of diverging part is different but in actual case stagnation pressure is constant at all location of part
Well done. The execution and example where just excellent thank you!
Sir best video. Example superb.
Suppose we want to measure the static pressure at Central line of pipe.So static pressure will not include hydrostatic pressure ( due to weight of fluid) because we are giving piezometer tube at surface of the pipe?
According to me static pressure should be due to pipe internal pressure plus hydrostatic pressure
Nice explanation ❤
Best explanation of the pressures
Good explanation of stagnation pressure
Thanks a lot, the animation really helped to understand static pressure, and stagnation pressure.
Good explanation
In diffuser example, as bernoulli states total pressure at inlet & outlet is same. But you said stagnation pressure at inlet is higher than outlet, which equal to total pressure in our case(z1=z2, no potential pressure)???
Bernoulli states constant total pressure along streamline, So how fluid flow if there is no pressure difference??
Same doubt
thanks for explanation
Best explanation for stagnation state
Excellent presentation regarding this topic, thanks a lot
i never usually comment but seriously GREAT EXPLANATION !!!!!!!!!
Excellent
very very good explanation. Thank you very much for this
Great
THIS IS GOLD!!!
THANK YOU!!!
Awesome
Superb❤
Really great video,much understood. But the nozzle and diffuser topic confused me quite a lot. Maybe i am missing out on some basic rule,but according to Bernoulli's rule should not the total pressure be the same on both sides? (Along a single streamline) thanks a lot!
Bernoulli states that total energy (kinetic energy, potential energy & pressure energy) remains conserved in a streamline and not just the pressure energy. Hence the loss in pressure energy in a nozzle is compensated by the increase in kinetic energy i.e., velocity. Hope it helps.
if you are moving with the water, i really don't think what you felt is "static pressure"
static pressure is the pressure you feel pressing against you when the water is still ( hence static, not velocity bound, it's the P component + h component of bernouli equation)
dynamic pressure is the pressure the water has when it is moving in it's direction
the pressure you feel while you move with the water ( assume single direction water movement ) is more of drag force
The pressure you feel when the relative velocity between you and water becomes zero is the static pressure
Beautifully explained 👌
Nice explanation sir ,thanku
very good video.... great work
I must say this was a great explanation
Nice explanation. As I understood from your reply regarding the total pressure equal to (static pressure + dynamic pressure + potential head or elevation), so the static head is different from elevation head, my question is: Why In a pump system the total static head is described as elevation difference between suction and discharge? Thanks in advance.
Because pumps increase static pressure of the fluid and this and this change in static pressure helps pump to raise water to that rated elevation depending upon the resistance in the pipe
Thank you ❤️
If the static pressure is caused by normal stress, is this accounted in bernuoulii’s equation? Since in that equation, visccity is considered neglible. Do we consider static pressure constant or zero?
Total pressure through noz/dif is constant
I don't get the down-votes.. This is by far the best explanation of dynamic pressure that I found.
Shandar samjhaya hai bhai
Good
Great explaining.
The difference of stagnation and static pressure = dynamic pressure only holds for mach number ( M
thank
great explanation. Thank you!!
so why moving fluid not exert force on adjacent surface of element inside fluid?? While they move and have kinetic energy but not contribute to collision between adjacent layer?
👍
"Dynamic pressure is due to the kinetic energy in the fluid" I think I get that..
A very good explanation
Good Explanation
Well Explained!
Jaan lene vala, jaldi samajh me aa gaya
Can u explain pressure gasses pressure in a cumbustion chamber and Diffrential pressure of the filter.?
well done, thank you
Can u expalin why we use stagnation pressure in case of centrifugal pump i.e npsh
Great example at the end. Thank you.
just the first part confuses me a lot, the nozzle and diffuser part
Gusecua Thanks for Your concern.
Fluid flows from high pressure to low pressure, is the obvious case. but if we look at the flow in nozzle and diffuser in steady state.
NOZZLE:- If you observe the static pressure on left section of nozzle, It is higher than static pressure on right side.
DIFFUSER:- If you observe the static pressure on left section of diffuser, it is lesser than static pressure on right side.
Important to observe that in both cases( nozzle and diffuser) fluid flows from left to right but pressure variation is not same. In nozzle it is high pressure low pressure and in diffuser low pressure to high pressure. But the pressure which we are observing here is static pressure.
" FLUID FLOWS FROM HIGH PRESSURE TO LOW PRESSURE WITHOUT ANY EXTERNAL FORCE"
This statement holds true for only for TOTAL pressure not static pressure.
I hope this will clear your doubt.
@@ClariFLIXConcepts best explanation sir.... 👌👌
At 1:55, How is total stagnation pressure higher at Section A than Section B? No energy losses are considered, right?
same question bro
This was perfectly explained!!!!
1) Please show the direction of static pressure and direction of dynamic pressure on a fixed point in a moving fluid
2) Does the stagnation pressure remain same at any section of the flowing fluid as per conservation of energy in a invicid , incompressible fluid.
Best explanation
In Bernoulli's equation, what is the difference between kinetic energy and energy due to dynamic pressure then?
Thank you! Much clarifying!
Amazing sir
You're my hero!!!
wow yaar amazing
How dynamic pressure is measured? For static pressure we use piezometer , for stagnation pressure we use pitote tube
Thanks for concern,
There is no such device, which can measure dynamic pressure directly, but theoretically if you can measure velocity then you can get idea of dynamic pressure.
For that you have to consider a probe ( weightless ), by stroboscope, measure the velocity and You can find dynamic pressure.
ClariFLIX Concepts can you explain little about pitote static tube
In pitot tube, one hole is provided on tip of the tube which is in the direction of flow. And more holes on the periphery.
And a manometer is attached between the hole on tip to the holes on the periphery.
Case - 1:- Fluid is not in motion.
As per the Pascal's law pressure experienced by hole on tip and hole on periphery will be same.
There you will see same elevation on both limbs of manometer.
Case - 2:- fluid is in motion
When fluid is in motion, flow will strike on the hole at the tip, flow with higher velocity will provide some more pressure.
While holes on periphery will have no effect due to velocity, because flow will not strike at the hole. Hence pressure will be comparatively lesser than pressure on the hole at tip.
As result of that in manometer you will see the deflection in elevation. Limb which is connected with hole at the tip will be having more pressure comparing to the limb which is connected to holes on periphery.
Pressure on limb which is connected to the hole at tip is Stagnation Pressure.
Pressure on the limb which is connected to holes on periphery is static pressure.
Difference between these two will give you the Dynamic Pressure.
ClariFLIX Concepts sir pitote tube and pitote static tube is different pitote tube measure stagnation pressure and pitote static tube measures dyanamic pressure that I have studied but confusion with pitote static tube
Diagram of both will give you more idea. You can raise you query to clariflixconcepts@gmail.com
What is the reason for static pressure? Or what is the source for static pressure? Or why there is a static pressure?
Hello Raja,
The source of static pressure is normal stress acting on the fluid medium. In addition to that, the rise in piezometer is just because of the incompressible fluid. As the normal stress acts on the incompressible fluid it rises in piezometric tube.
@@ClariFLIXConcepts sir is static pressure due to weight density of fluid and changes with height h.
You are not Wrong. But the statement is partially correct.
Consider pressure on surface of Ocean.
That is 1 atm pressure. As you go at the bottom of Ocean. Static pressure will definitely increase this can justify your statement... " Static pressure is due to weight density."
But you know as we go upward direction of ocean static pressure reduces. Can you justify this thing with your statement?
@@ClariFLIXConcepts Actually we see the value of h from free surface of water. More the height from free surface of water, more will be static pressure.
I do not agree. As stagnation pressure, as per Bernoulli equation, is constant along diffuser/nozzle. Can you clarify?
Why the fluid level inside the piezometric tube raises due to static pressure,
The term static pressure in flow is due to uniform or steady flow?
thanks for this video.what is relation between pressure and potential energy?
Thanks for concern,
Your doubt is regarding pressure and potential energy?
Or
Pressure energy and potential energy?
Sir it means stagnation pressure is total pressure acting on a stationary particle in a moving fliud.?
It would be better, if there was an english subtitles for non-english speakers
Thank you! But 1 very impt question: where does the Static Pressure of moving water in a tube come from? I have problem understanding where the Static Pressure comes from.
It comes from the collision of the fluid particles with the walls of the object placed in the fluid .
Nice
Could I clarify whether dynamic pressure in the pitot tube basically represents the amount of kinetic energy that was converted to pressure energy and its shown by the "Dynamic Head" pressure rise in the pitot tube
U are right.
I used to see this video more than 3 times then only I understood it means my IQ level is quiet Low 😂😅
I have a small query...according to Bernoulli's theorem, if area is reduced, then velocity increases & pressure reduces but doesnt it happen, that when u squeeze a water spraying pipe, its vel & pr both increase? Can u kindly explain?
Thanks for concern,
While pressing the spray air flows with higher velocity through pipe, The flow of air at a high speed creates a region of low pressure just above the tube, which allows the water to leave the tip of the tube through the nozzle as a fine spray, carried by fast moving air.
thank you alot sir,i have a question which is the difference between hydrstatic pressure and static pressure?
th-cam.com/video/2-jl2jObj4E/w-d-xo.html
May I know about total pressure
Static pressure also called pizometer pressure
Yes, Static pressure is also called as piezometric pressure. Because it is measured by piezometer.
can you explain whats the difference between stagnation and total pressure?
Dear Yashawant,
Stagnation pressure is the summation of static pressure and dynamic pressure whereas the Total pressure is the summation of static pressure, dynamics pressure and pressure due to potential head (P=rho*g*h). This means that the Total pressure also includes the potential energy of the fluid over and above the static pressure energy & kinetic energy whereas Stagnation pressure includes only the static pressure energy & kinetic energy.
If you look at the Bernoulli's equation you will find the three different terms, one is for static pressure, second is for dynamics pressure and third is for the pressure due to potential head. So addition of all these three terms will give you total pressure whereas addition of first two terms will give you stagnation head.
Stagnation pressure represents the energy contained by the fluid by the virtue of pressure and motion whereas Total pressure reflects the energy contained by the fluid by the virtue of pressure, motion and position too.
I hope you got your answer. In case if you still have some query, kindly reply back with your query.
ClariFLIX Concepts very nice explanation...clear all my doubt...thank u
Thank you.
But I have a small confusion; If flow occurs from high stagnation pressure to low stagnation pressure (P + 0.5*v^2/g), Why doesn't water flow from the bottom of the water beaker to the top of the beaker? Because as I see it, the velocity is zero at both points but there is a difference in static pressure.
And second if it is not the stagnation pressure difference that makes a fluid flow, What does?
Hello Hiras Ahamed,
Thanks for asking question.
To understand the answer, Consider all particles at the bottom of vessel, they are having more stagnation pressure BUT for all those particles to reach at the top of the vessel they need to overcome the weight of all the particles situated above those particles and frictional loss among all particles too, that is the reason why the water particles from bottom do not raech at top.
Okay. Thanks for the reply
Hello Hiras Ahamed,
I would like to add few more points for better clarity of the concept. You need to understand the difference between the total pressure and the stagnation pressure. Stagnation pressure head constitues of static pressure head and dynamics pressure head (P+0.5*V^2/g) whereas the total pressure head is the summation of static pressure head, dynamics pressure head and potential head (P/(rho*g)+0.5*V^2/g + h).
In general fluid flow, the flow always occurs from high total pressure to low total pressure. But when you talk about the device placed parallel to ground (horizontally) where the flow is occuring in horizontal direction, the potential head is always constant.
For the horizontal flow, either of the following statements holds true,
1) Fluid flows high total pressure to low total pressure.
2) Fluid flows from high stagnation pressure to low stagnation pressure. (As the potential head remains constant)
In this lecture we talked about nozzle and diffuser placed horizontally, so we used second statement but it can not be used to judge the flow direction if there is change in the vertical elevation in the pipe. First statement is applicable in general of any flow conditions.
Now coming back to the question you asked about the flow of water from the bottom of the beaker to the top surface. Here you talk about the flow in vertical direction so we have to use the first statement which says that "Fluid flows high total pressure (P/(rho*g)+0.5*V^2/g + h) to low total pressure (P/(rho*g)+0.5*V^2/g + h)".
Now let us calculate the total pressure at both these surfaces,
for an instance consider that the vertical difference in the elevation of these two surfaces is "z" meters.
a) At the top surface P=0 gauge, V=0 & h= z (considering the datum line at the bottom surface)
so Total pressure at top surface = z
b) At the bottom surface, P= rho*g*z (as per the principle of fluid statics, V=0 & h=0 (as bottom surface is at datum))
So total pressure at bottom surface = P/(rho*g)= (rho*g*h)/(rho*g)= h
Hence total pressure at both the surfaces is equal which means flow will not takes place in any of the direction (neither upward nor downward). Fluid at such a state can be examined by the branch of mechanics called "Fluid Statics".
I hope you understood it. If you still have some doubts, feel free to post it here.
Thank You.
ClariFLIX Concepts
Your explanations are amazing
Very well explained
stagnation pressure and total pressure are same or not?
Stagnation pressure includes kinetic head and pressure head wherever total pressure includes kinetic head, pressure head and potential head.
What about the flow in diffuser if stagnation pressure at both ends of diffuser is same !?
Thanks for your concern,
It is not possible to have a flow having same stagnation pressure on both the ends.
In case of diffuser, It is must to have less stagnation pressure at the exit than inlet stagnation pressure.
Can u show how the stagnation pressure is less at the end of the diffuser? If we consider a particular streamline there the stagnation pressure remains constant and to maintain the stag const the velocity and pressure is changing then how stagnation pressure is changing?
hey...how can u feel dynamic pressure..?
i mean u can feel other two pressures...but its the difference both...but im not getting how or where can i feel dynamic pressure..plzz help
You can't really feel dynamic pressure, feeling dynamic pressure would just be how much more you feel the stagnation pressure vs the static pressure.
@@CockatooDude k ty ✌
V for velocity or volume???
Its velocity.
At stagnation point velocity of fluid is zero or not ?????
Yes, at stagnation point velocity is zero.
@@ClariFLIXConcepts tx sir..
Definition to Bata detay bhaiya not right from me
Damm it, I can't understand english with indian accent!
If the flow is incompressible what pressure should we measure total pressure or static pressure???
If the static pressure is caused by normal stress, is this accounted in bernuoulii’s equation? Since in that equation, visccity is considered neglible. Do we consider static pressure constant or zero?
As of we are assuming frictionless flow ( zero viscosity ) the static pressure will remain constant.