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Questions tagged [bernoulli-equation]

An equation governing fluid flow for an incompressible steady fluid

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Stagnation pressure on an accelerating surface

The usual stagnation pressure $P_0$ on an object (e.g., a sphere) moving at velocity $U$ is simply $$ P_0 = P_\infty + \frac{\rho}{2}U^2$$ where $P_\infty$ is the pressure of the free stream. If ...
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Bernoulli question from a layman

So my understanding is that pressure and velocity are inversely proportional. If I where to go from an 8" pipe to a 4" pipe the velocity would increase thus a decrease in pressure. Pretty straight ...
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Velocity of fluid dividing to two different paths [closed]

Fluid of density $\rho$ is flowing through a pipe with area $A$ with velocity of $V$. The pipe divides into two different pipes of area $\frac{1}{2}A$ and $\frac{3}{2}A$ with the right end opened. All ...
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Can you explain the perfume bottle with the Bernoulli effect?

Someone explained the perfume bottle with the Bernoulli effect: squeezing the bulb over the fluid creates a low pressure area due to the higher speed of the air, which subsequently draws the fluid up. ...
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Velocity of a leak in a cylindrical water tank that spins with constant angular velocity

We have a cylindrical water tank that spins over its axis of symmetry. Here's a diagram: The objective is to find: $1$ - The tangential and radial components of the velocity of the water as it ...
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Differential pressure sensor applications

I have two differential sensors and in my experiment I wish to measure the air pressure from below and on top of the ball that is levitated by air. These are my 3 possible setups. Considering the 3 ...
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Is it correct to use Bernoulli's theorem to explain that a disk floats in the air? Should the correct explanation be based on Boyle's law?

In this video, a device is introduced from 1 minute to 18 seconds. After entering the air, the disc at the bottom of the device will be suspended in the air. The video explains that this is because of ...
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If Bernoulli's Principle may leads to a collision between two ships, then will it happen in a multi-ship situation?

I mean several battleships sailing on a sea towards the same direction. Some of them are parallel with short distances between each other. Could the pressure difference be cancelled out?
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Bernoulli Principle at a Microscopic Level

Good evening, kind forum users. I'm trying to understand the microscopic mechanisms that justify the Bernoulli principle. I found an interesting discussion on the site of NASA that tries to describe, ...
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1answer
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Height of Fluid in circular motion

I have a question regarding the the height of a fluid spinning due to a drain in a sink. We are following Feynmans Lecture of physics. It should be "easy to see" that, that the height is something ...
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Should I use a barometric pressure sensor (BME280) or a differential pressure sensor (MPXV7002DP) to measure the airflow and pressure in an open tube?

I'll elaborate more on my set-up. I have a an acrylic tube and inside the tube is a ball one side has a dC fan to output air and the other side is a small cover just to not let the ball escape from ...
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Pressure Difference in a Rotating Fluid Coloumn [closed]

This question has intriqued me because two methods are generally employed to derive the shape of the surface(paraboloid) . Both methods give equal numerical answer but differ in which of them P or Q (...
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Why can water be sprayed farther when the pipe outlet is narrowed?

Someone told me: This is because the flow rate remains unchanged, so the flow rate of small diameter pipelines is faster. I don't think this explanation is right: the diameter of the pipe outlet is ...
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Can Bernoulli Equation be applied across two fluids?

There is a beaker with two liquids placed above another. The beaker has a hole at bottom. So can I use Bernoulli equation across the interface of liquids.
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Bernoulli equation: how should one imagine $\frac{p}{\rho}$?

The Bernoulli equation states the following $$ \frac{1}{2}u^2 + \frac{p}{\rho}+ gz = \text{constant along a streamline} $$ where: $u$ is the fluid flow speed at a point on a streamline, $g$ is ...
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Is it true that we can speak, sing, and play wind instruments due to the Bernoulli effect? [closed]

Is it true that we can speak, sing and play wind (brass) musical instruments due to the existence of the Bernoulli's Principle ?
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Outflow velocity from a funnel over time for water without the simplifications made in Torricelli's law

I am trying to calculate the outflow velocity $v_2(t)$ from the orifice of a funnel for water. I am aware of Torricelli's law derived from the Bernoulli equation assuming $v_1(t)\approx 0$ resulting ...
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Measure static pressure with measuring tubes of different diameter

Assume you have a horizontally placed cylindrical pipe with constant diameter. There is a flow of water, through this pipe. You want to measure the static pressure inside the tube, which should be the ...
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Feeling low pressure fluid with high velocity

In Bernoulli theorem physics we say that pressure is low when velocity is high but we feel pressure when fluid hits us why?
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Does the pressure caused by the force exerted on an ideal fluid in a Bernoulli tube decrease over an increasing distance? [closed]

Does the pressure caused by the force exerted on an ideal fluid in a Bernoulli tube decrease over an increasing distance? For example, someone pushes the water with a force from the left in this setup....
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How pressure and velocity is related? And its effect in cavitation

As per my knowledge I think when velocity increases and discharge is constant,the fluid(liquid) molecules get away from each other in the region where velocity is high and that's why they get ...
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Bernoulli Experiment- why is the pressure on the left greater? [closed]

Is the Pressure $P_2$ caused by a reaction force to the fluid-fluid collision, or is it the result of the collisions of the water molecules with the walls at the neck of this experiment. The part ...
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1answer
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Bernoulli's equation basics

While deriving the Bernoulli's equation, we write the change gravitational potential energy as $mg(h' - h)$ , say where $m$ is the mass and $h'$ and $h$ are the two heights. Why we don't consider the ...
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Pressure in a moving fluid

I’m having some quite large conceptual difficulties which I hope can be resolved by considering this example. When considering the pressure in the sheet very far away from the impact zone the ...
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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 ...
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Material Derivative in Fluid Dynamics and Bernoulli Flow

If a fluid flow, such as water, is incompressible then the convective derivative term in the material derivative is equal to zero. How then, in a Bernoulli flow where there is an increase in velocity ...
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Bernoulli Experiment, unanswered questions

In the bernoulli experiment, the pressure on one side is greater than the other, thus the fluid flows faster through the thinner nozzle.In the image, is the pressure created shown correctly? Since ...
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Question derived from Bernoulli's book “ Hydrodynamica” and his contribution to atomic Theory

Here is the extract from the book Now the weight $π$ is sought which can compress the air $ECDF$ into the space $eCDJ$, the velocities of the particles in either air (the natural and the ...
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Does bernoulli's principle explain the suction by an emerging air stream?

Consider flow exiting a nozzle into atmosphere, its static pressure will decrease through the nozzle as the molecules vectors align with the direction of the exit. However, as soon as it exits the ...
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1answer
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Why does a ping pong ball on a string move toward a running stream of water?

We keep a ping pong ball on a string near a faucet but not directly under it. When we run the water, the ball moves to the stream and sticks there. I'm only interested in the moving part not the ...
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How does a sonic jet attenuate a sound wave?

Let's assume air flows through a pipe and exits into free atmosphere. The atmospheric pressure is below the critical pressure of the flow, hence the gas is accelerated and a sonic jet forms at the ...
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Couette Flow encountering an airfoil obstruction

Im interested in what would happen to an airfoil place within a Couette type fluid flow bounded between a fixed and moving boundary plate If we say the plate is infinite to establish a steady state ...
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4answers
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Calculating value of $g$ from Torricelli's law

For my Physics project, I decided to do an experiment with fluids. I'm using the Torricelli's law to verify that the value of acceleration due to gravity on earth is $9.81m/s^2$. I am using the ...
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Magnus effect without windspeed

Canagnus effect take place if windspeed is 0 ? Lets assume that our frame of reference a place an earth (e.g. soccer pitch) .We measure the windspeed and we find it zero.But if we make a knuckleshoot ...
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Bernoulli principle and relativity [duplicate]

Bernoulli principle has many applications like airplanes take off etc. But when we apply Bernoulli's principle we dont refer the reference frame in which we measure the velocity of air for example. ...
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Applying Bernoulli's equation in fully developed viscous pipe flow

Can we apply the inviscid Bernoulli equation $$ \frac{P}{\rho} + \frac{1}{2}V^2 + gz = constant$$ along the center line of a fully developed pipe flow? I think we can since the shear stress along ...
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Do the height of the water columns decrease when we push pistons with constant speeds in this venturi pipe?

Let say when the pistons are kept stationary the height of the water columns are h. And we start exerting extra force on the left piston in figure, and the pistons are moving with constant speeds. ...
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Proof that pressure rises in a fixed control volume

I am looking for a proof using Bernoulli's equation that that for $Q=(Area)(Velocity)$, $Q_{in}>Q_{out} \Rightarrow P_{inside}>P_{outside}$. I read that for a computer, if the case fans blow a ...
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Principle of Lifting of an Aircraft [duplicate]

While using the Bernoulli's equation to deduce the upthrust on an aircraft , a statement is always made that The air particles going above th wing have to cover a greater distance in same time than ...
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Increase Air Speed at outlet

I have a set up that inflates a rubber jacket in order release the metallic rings from underneath it. I am currently having issues with not having enough pressure (force) at the outlet to inflate the ...
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How to use General Energy Equation in parallel pipes?

My question comes from exercises with parallel pipes such as this. I know that to analyse internal flow, we use general energy equation which origins from the 1st law so each time we apply it we are ...
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Limitations of converting pressure into kinetic energy

Bernoulli's principle states that an increase in the kinetic energy of a fluid occurs simultaneously with a decrease in pressure for isentropic processes. What then limits us from converting all of ...
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Pressure in speed of efflux

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?
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What does the term $P$ represent in Bernoulli’s equation?

$$P+\rho gh+\frac{\rho v^2}{2} = C$$ Does the $P$ here stand for the hydrostatic pressure exerted by the fluid on its surroundings or the pressure that’s exerted on a given portion of the fluid? I ...
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Bernoulli's principle for a liquid with non uniform density

Consider a cylindrical container (section $S$, height $H$) which contains a liquid with non uniform density. Let $z$ be the axis along the height of the container ($z = 0$ indicates the top of ...
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Pressure distribution around an aerofoil

Some notes that I'm reading right now show a picture of the distribution of pressure around an aerofoil with zero angle of attack. The notes say that the pressure is identical at the top/bottom ...
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1answer
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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 ...
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Deriving relationship about water not falling down from a hole under a fast flowing stream [closed]

A gutter is tilted from an angle of $\theta$ with respect to earth. There is a hole on the gutter from a distance of $l$ (m) from the top of a gutter. What is the speed of the water that should flow ...
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Relationship between blood pressure and cross sectional area of blood vessel

What is the reason why blood pressure and a larger cross sectional area of blood vessel cause a lower blood pressure and vice versa? This question is related to another question I found here. The ...
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Why water doesn't drop down from a hole when a stream of water travels fast over it?

why water doesn't fall down from hole on the roof when its raining heavily (water moves fast on the roof) ? Can I know the theory behind this and the factors affecting?