Questions tagged [bernoulli-equation]

An equation governing fluid flow for an incompressible steady fluid

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31 views

Wich is the correct flow rate $Q$ solved with iterations?

I have a little question about this problem I computed the right answer this way First I applied Bernoulli between the top and the exit $$\frac{P_{t}}{\rho g}+z_{t}+\frac{v_{t}^2}{2g}-H_{1}-H_2-H_{\...
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This is my bucket experiment. I use this experiment to explain lift. Am I right?

Hang the bucket on a long rope. Rotate the bucket to tighten the rope. Then fill the bucket with water and close the lid (shown in the blue line). At this time, the bucket and water are in a static ...
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Problem estimating the flow rate in natural draft chimney using Bernoulli equation including heat and friction losses

I am trying to build a simple model for fluid flow and heat transfer in a natural draft chimney. I've found some literature about it (most of them giving the same result as the equations on the ...
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Why does blood pressure drop when blood vessels rupture?

Some people say that because the flow is large, the pressure is low. Is that right? Why does the pressure drop when the flow rate is high?
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What exactly is $p$?

Consider the Bernoulli equation of fluid dynamics. One of the terms is $p$. I know it is pressure. But what type of pressure is it? Is it pressure due to height or a completely different concept?
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Bernoulli's theorem in water flow through a burette

Consider a burette (like the one in a chemistry lab) with uniform cross-section and open at both ends so that they are exposed to the atmosphere. Once we open the stopcock/plug (P in the diagram) the ...
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65 views

Bernoulli's equation's contradiction

Using Bernoulli's equation P Pressure p density V velocity of fluid $$P_1+ \rho gy_1+\frac{1}{2}\rho V_1^2 = P_2+\rho gy_2+\frac{1}{2}\rho V_2^2$$ $$V_1^2-V_2^2 =\left(2g(y_2-y_1) +\frac{2(...
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Clarification on Bernoulli's Principle

I need a clarification about Bernoulli's principle. The standard way in which this principle is taught is related to a picture like this one where usually the two sections have different areas and ...
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What is the lift coefficient of human body?

Assuming we can change angle of attack by changing our hands orientation what is the maximum aerodynamic lift coefficient of human body?
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Can Bernoulli's theorem be applied to laminar flow?

Since in streamline flow the velocity of a particle at any point is same, Bernoulli's theorem can be applied to streamline flow, but could it be applied to laminar flow?
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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 ...
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Please explain airflows above and below aerofoils for a layman

I have read about the lift of aerofoils a lot recently and just want a few things cleared up. When incoming airflow hits a typical cambered aerofoil and diverges into "top" and "bottom" airflows, why ...
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71 views

Bernoulli's equation in system of coupled tanks

Problem statement. Consider a system of two coupled tanks as the one shown below Several authors such as Bistak and Huba, 2014, Sim et al, 2017, Khalid and Kadri, 2012, Essahafi, 2014 claim that ...
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Flow equation for system of coupled tanks

Consider the following system of interconnected tanks: The two tanks have cross-section areas $A_1$ and $A_2$ respectively and the levels of the liquid are denoted by $h_1$ and $h_2$ respectively. ...
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Is Bernoulli's equation the correct explanation of a curved soccer ball? [duplicate]

I saw a lot of materials supposing that the Bernoulli's equation explains the curvature of a soccer ball: since the ball is spinning, two sides of the ball would experience different velocities, and ...
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115 views

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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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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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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196 views

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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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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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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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 ...