Questions tagged [bernoulli-equation]

An equation governing fluid flow for an incompressible steady fluid

Filter by
Sorted by
Tagged with
0
votes
1answer
39 views

Pressure Variations in an Atomizer

This question has been asked two times Similar question 1 Similar question 2 Now my question will be different from all those questions, since I will be asking where exactly I am having trouble ...
0
votes
1answer
1k views

How does this spray gun work?

This is the critter spray gun. The liquid in the jar is at atmospheric pressure (there's a vent hole connecting it to the atmosphere). A fast jet of air flowing right over the end of the pickup tube ...
0
votes
3answers
97 views

Why do we need to do work to maintain motion of a fluid?

On page 355 of principles of physics by Resnick walker and Halliday, the author writes: Work must also be done on the system (at the input end) to push the entering fluid into the tube and by the ...
3
votes
1answer
103 views

Concept regarding Ventury Tube-Bernoulli application

I was recently studying applications of Bernoulli Equation and came across the Ventury tube. This is diagram I have used to analyse the venturimeter. I understand how we obtain the first equation ...
0
votes
1answer
40 views

Zero velocity at a point in a streamline

Given a streamline, is it possible that the velocity at some point on it is non-zero but then at some other point(for example, stagnation point) it is zero? I mean does that make sense? My existing ...
1
vote
2answers
2k views

Maximum liquid velocity in a siphon

According to wikipedia: Siphon, the velocity of liquid in a siphon is equal to $\sqrt{2gh}$, where h is the difference in level between the water surface and the opening of the siphon. But it also ...
0
votes
1answer
16 views

Pressure at the opening of tube in Siphon

Consider a siphon tube... Now consider the opening of the tube at the lower end. Isn't the pressure at the mouth of the tube, at this lower end, something intermediate between $P_a$ and $P_a + \rho gh$...
0
votes
1answer
199 views

How to find velocity of water flow and $Q$ if I know static pressure at the end of the pipe of known diameter?

I have a pipe. At its end I have mounted pressure meter. Of course there is no circulation. Water pressure meter is a kind of stopper for water. I know diameter of the pipe, and I know its pressure in ...
0
votes
2answers
53 views

Explain hydrodynamic Levitation

I had researched it and I saw everyone has there different answer. Someone says its Magnus effect, someone says it is Coanda effect and someone says its Bernoulli's principle. Can it be specific? What ...
-1
votes
1answer
44 views

Explaining Bernoulli's Principle

I'm trying to explain Bernoulli's principle (in the context of flight) to an audience that doesn't have a physics background. So I'd like to avoid mentioning technical concepts as much as possible. ...
0
votes
5answers
2k views

Why doesn't Bernoulli's Principle apply to Current and Resistors in a circuit?

Bernoulli's principle makes sense when you apply it to fluids. If you decrease the diameter of a pipe then the velocity of the fluid increases because it needs to keep the same rate of fluid moving ...
1
vote
1answer
319 views

What is the relationship between flow work and velocity of gas?

As we know that for open systems, we have energy conservation equation as $$h+\frac{v^2}{2}+zg=const.$$ $$h=u+pV$$ $$u+pV+\frac{v^2}{2}+zg=const.$$ Here $pV$ is flow energy. We know that all these ...
4
votes
1answer
147 views

Flow through a hole in a sphere

I have a sphere of diameter $D$ (radius $R$) with a small hole of diameter $d$ (radius $a$) in it, with air flowing through the axis of the hole: I am trying to estimate the drag force due to ...
2
votes
3answers
191 views

Confusion about Bernoulli equation

Suppose I have a fan blowing air. By Bernoulli's equation, the air pressure in the stream is lower than the air in the surrounding. Here is my confusion: the moment I turn on the fan, the fan starts ...
0
votes
2answers
149 views

Bernouli equation on streamline

I made my first point at the free surface of the water and my datum to be the very bottom. Part (b) of the question asked to find the velocity of the water in the pipe. I set my second point to be at ...
1
vote
3answers
136 views

How does one calculate the expected leak rate through a hole, and the pressure drop due to that leak?

Let's say we have a pressurized horizontal tube that has a hole along the way. What would be the flow rate through that hole, and what would the pressure be downstream of the hole? Or if you prefer ...
0
votes
2answers
333 views

What happens if a helicopter's propeller spins in reverse?

I know airplanes and helicopters fly thanks to the same principle, the Bernoulli Principle. The wings and blades are designed so that the air travels faster across the up side than it does on the ...
-2
votes
1answer
24 views

Is there a drag in a moving fluid due to pressure (reaction) from the walls of the tube?

Consider a tube of linearly varying cross section... Now consider a section of the tube...There are pressure on the ends of this section due to the fluid... Now consider the walls, there is a ...
1
vote
3answers
386 views

Doubt in derivation of Velocity of efflux (Torricelli's theorem)

To find the velocity of efflux of fluid from a hole in a simple cylindrical container we use the Bernoulli's equation. $$P + ρv^2/2 + ρgh= constant$$ For our specific case we take the pressure at ...
1
vote
2answers
36 views

Intuitive explanation of the causality behind a pressure gradient forming

The Bernoulli equation as a statement on the conservation of energy as I understand it is the observation in an idealized flow that the bulk fluid velocity relates to the kinetic energy of the fluid ...
2
votes
2answers
128 views

How to determine effect of obstruction on pressure?

I am struggling to figure out what theory explains a situation I observed. A steam boiler had a pressure control which would turn off the boiler if it sensed 2 psi. The boiler would frequently switch ...
0
votes
1answer
149 views

Do viscous and inviscid flow have opposite effects on pressure?

Consider flow through the converging and diverging portions of a tube with varying radius: In inviscid flow, Bernoulli's equation states that velocity at the throat will be the highest, so this area ...
0
votes
1answer
49 views

Semantic question about Pressure in fluid

I have a semantic question about Bernoulli's equation, I learned that Bernoulli's equation is: $$\frac{v^2}{2} + \frac{P}{\rho} +gy=const.$$ My question is why is it that at point $C$ the pressure is $...
0
votes
1answer
233 views

Question about Airy wave theory

I have a fundamental misunderstanding about Airy wave theory. All the texts that derive the dispersion relation for gravity water waves use as a final step the unsteady Bernoulli equation: $$\frac{\...
0
votes
1answer
58 views

Why does the pressure inside a pipe momentarily increases when the tap is closed?

I fill coolers in my house with a pipe connected to a tap, as soon as it is full i place a thumb on the open section of the pipe effectively shutting off the outflow of water. Keeping my thumb in ...
0
votes
1answer
304 views

Reconciling $Q=PR$ and $Q=vA$

Say we have a closed loop system, where the flow $Q$ is constant through a pipe. Then, at one segment of the pipe, we make the radius smaller. This causes the resistance $R$ to be greater, so the ...
14
votes
3answers
3k views

What force accelerates a liquid moving in a narrowing pipe?

Say there is a liquid which behaves like an incompressible fluid and is flowing steadily through a pipe which is moving from a cross section of area $A_1$ to the cross section of area $A_2$, where $...
1
vote
1answer
558 views

If the difference in pressure is zero between two points of a horizontal constant radius pipe, why isnt flow rate zero?

In a straight pipe of uniform cross-sectional area filled with a nonviscous, incompressible fluid, the pressure at one end is equal to the pressure at the other end. Which of the following statements ...
5
votes
4answers
402 views

How does high velocity cause low pressure? [duplicate]

Bernoulli's principle states that air molecules moving with high velocity create an area of low pressure which in turn causes an object to fly, but how does high velocity cause low pressure?
0
votes
0answers
18 views

About deriving bernoulli equation from particle model and its pressure difference

Here i added a page from my fluid dynamics book where it shows particle model for deriving the equation. My question is why pressure is more at stream side aka 'positive "s" direction'.I would ...
3
votes
1answer
51 views

Does Bernoulli's equation describe why my curtains stick to the mesh?

I was sitting right in front of a big window (with a mesh) with curtains open, suddenly wind swooshes in, curtains sway forth and back. While they sway backward, they stick to the window(mesh) as if ...
1
vote
2answers
30 views

Does the number of holes in the bottom of a bucket determine the height at which the pull of gravity overcomes the surface tension?

Ok, my colleague and I are having a debate that we need help with. Neither one of us works in this space (chemist and materials scientist) and we understand this should be pretty straight forward ...
0
votes
1answer
993 views

How to apply Bernoulli's equation on an experiment of rising water with a straw?

Consider the following experiment: Rising a water in a straw. For the sake of simplicity, let me assume that there is no air in the straw by redefining the height h...
0
votes
1answer
27 views

Does high pressure force an object to a lower pressure area?

Suppose a ball is spinning through mid air. We know through the Magnus effect the way the ball will go. On the side where the air flow is slowed down due to the spin of the ball, the pressure ...
1
vote
3answers
523 views

Centrifugal Pump Head

What is pump head? and how is it different from the difference in elevation between the suction and delivery reservoir? Also why must the kinetic energy of the fluid leaving the pump must be least? I ...
0
votes
1answer
35 views

Why does the air flowing above the aerofoil moves faster than the air flowing below the aerofoil? [duplicate]

https://www.youtube.com/watch?v=UqBmdZ-BNig why can't it be the other way around that the air flowing below the chamber moves faster than the air moving above the upper chamber?
5
votes
3answers
70 views

A contradiction from two reliable sources on the principle of how siphons work

At 39:08 of Lecture 28 of 8.01x by Walter Lewin, a water siphon would not work if the distance is over 10 meters due to the barometric pressure. However, this claim is seemingly refuted by Periodic ...
0
votes
2answers
38 views

How does pressure become velocity in a jet engine axial turbine?

All right. Here's what I understand about axial turbines: It is an axial compressor in reverse. An axial compressor forces air to flow in an increasingly tight space, where there is not enough ...
0
votes
1answer
303 views

Mathematical description of Bernoulli equation and transition from laminar to turbulent flow

I am very interested in the mathematical description of the next topics: 1. Bernoulli equation 2. Transition from laminar to turbulent flow Could you help me ...
0
votes
0answers
20 views

Does the shape of the pipe (the length not the cross section area) affect resistive force?

Does the shape of the pipe (the length not the cross section area) affect resistive force acting on water? Does keeping the pipe straight or keeping it in curves folded over each other effect the ...
0
votes
2answers
25 views

When solving using Bernoulli's principle, is the pressure potential energy per volume of atmospheric pressure water 0 Pa or 100,000 Pa?

I was just given a question using Bernoulli's principle that gives you the pressure of water (e.g. $1,000,000 \mathrm{Pa}$) in a hose, and asks for the speed of the water after the water has left the ...
2
votes
3answers
348 views

Why don't we consider the pressure due to height of liquid column above the orifice while calculating the speed of efflux using Bernoulli equation?

While describing speed of efflux, using Bernoulli equation, we use value of $P$ at both openings as atmospheric pressure. Why don't we use $P_\text{atmosphere}+\rho gh$ for $P$ at bottom opening?
4
votes
4answers
293 views

Could the Bernoulli equation be explained by kinetic theory?

I have watched on the Youtube channel of Eugene Khutoryansky an explanation of the Bernoulli equation on the molecular level. It states that" An atom is more likely to enter the narrow section of a ...
1
vote
1answer
901 views

Static Pressure in a Venturi vs a Free stream

We seem to have two conflicting measures of pressure in a Venturi siphon open to the atmosphere,$\hspace{100px}$. Bernoulli's principle says that, by energy conservation for a steady flow $Q$, the ...
1
vote
2answers
3k views

Total and static pressure: which one is measured?

Which pressure is measure using measuring device in a pipe flow. My first intuition that it is the static pressure. This is confirmed by this Wikipedia article (link) The concepts of total ...
0
votes
1answer
164 views

Which equations recommend to model a flux through a Bernoulli tube?

Which equations recommend to model a flux through a Bernoulli tube? The velocity of the flow varies very little along the tube, in addition the tube has different transverse areas. I am doing a ...
5
votes
2answers
3k views

Inverted U manometer

I have some doubts on inverted U manometer. In the picture there is one U inverted manometer, the space above the liquid in the manometer is filled with air which can be admitted or expelled through ...
1
vote
1answer
196 views

Difference between Pressure and Pressure Energy in fluids

For a fluid with viscosity to flow through a pipe that has the same cross-sectional area at both ends, at a constant velocity, there has to be a pressure difference according to Poiseuille's Law. Why ...
1
vote
1answer
23 views

Calculating the flow rate in a non-ideal siphon?

When calculating flow rate in a siphon, the simplifying assumption is usually made that the velocity head at the input is effectively zero. This requires that the cross-sectional area at the input be ...
10
votes
5answers
446 views

Intuition behind Bernoulli's equation [duplicate]

If water is flowing from a larger subsection $A_1$ of a pipe into a smaller subsection $A_2$ (say, the radius halves), then Bernoulli's principle says that the pressure $P_{A_1} > P_{A_2}$, and $v_{...

1
2 3 4 5
8