# Questions tagged [bernoulli-equation]

An equation governing fluid flow for an incompressible steady fluid

320 questions
Filter by
Sorted by
Tagged with
10k views

### Is Magnus effect a corollary of Bernoulli principle?

Magnus effect is commonly explained using Bernoulli principle. However, taking the lift on a rotating cylinder as an example, the velocity difference is caused by the extra work done by the rotating ...
35 views

### How do I calculate the pressure $p_0$ on top of the water reservoir?

Can anyone help me with this question, I can't get the right answer :-) A water reservoir with depth D=200m, which is placed H=500m above on a mountain. A pipe is placed from the bottom of the ...
22 views

### Bernoulli (?) question? [closed]

can you help me to solve this problem? I have a pipe with water, at a constant pressure of 10 bar. I have then 3 holes, each one of different size and on an orizontal level. Out of which hole does ...
45 views

### Why moving train's windows slam shut when another train passes slowly in the same direction?

My question is related to this one but distinct as this case is trains travelling in the same direction. We're familiar with this scenario. You're sitting in train A and another passes at high speed ...
4k views

### Bernoulli's Equation for flow of gas and changing area

My task is to determine the size of piping needed in a system. In this system, hydrogen gas flows horizontally in a $\frac{3}{4}\,\mathrm{inch}$ pipe and into a vertical pipe of a larger diameter. My ...
499 views

### How does an aspirator pump work?

The below picture is of a aspirator pump. If we press the bulb at A the air in it with density $\sigma$ will flow out with velocity $V$. This would cause lower pressure at B and hence the liquid with ...
164 views

### 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 ...
16 views

### Does the pressure inside a rigid container change with velocity?

Say you take a parcel of air and place it inside a rigid container, like a glass bottle. Then put that bottle on a rocket sled and accelerate it to very high speed. Since the air inside the bottle now ...
175 views

### What does the pressure term in Bernoulli's equation signify?

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?
105 views

### Please explain airflows above and below aerofoils for a layman

I have read about the lift of airfoils a lot recently and just want a few things cleared up. When incoming airflow hits a typical cambered airfoil and diverges into “top” and “bottom” air flows, why ...
49 views

### What is the maximal velocity of air blown through a straw?

If an adult can buildup a pressure of 9kPa when blowing air through a straw then the pressure drop will be 0.5*1.25*v^2. But if I want to compute the air volocity in the straw how can I know the ...
2k views

### Application of Bernoulli's equation to siphon

I'm trying to understand how to use Bernoulli's equation in practice. So I will make an example of where is my confusion. I found this great explanation on Wikipedia about the siphon, but there is a ...
39 views

27 views

### 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 ...
327 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 ...
70 views

2k 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 ...
732 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 ...
97 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 ...
71 views

### 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. ...
28 views

### 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 ...
65 views

### 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. ...
40 views

### 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 ...
198 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 ...
820 views

### Bernoulli's principle

In steady flow, the air that flows faster causes a lower pressure, the lower pressure causes it to move faster, or exactly both at the same time? Also how is it that we're talking about the pressure ...
35 views

### 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 ...
72 views

### 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 ...
31 views

### 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 ...
19 views

### 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?
186 views

### 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?
61 views

### 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, ...