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Bernoulli's principle in moving car not works [duplicate]

According to Bernoulli's principle, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure. As I understand that also applies to gas or air. Ok, so when I open a ...
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1answer
27 views

What is the best way to calculate speeds at other points in a venturi-tube when knowing one?

I and a friend have made a venturi tube trough which water flows at a low speed. The flow is therefore laminar. We measured the static pressure using some piëzometers at the points 1,2 and 3. We know ...
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1answer
46 views

Finding the expression for the time it takes for a water tank to be half empty

The problem is to find an expression for the time it takes for a cylindrical water tank is half empty. I am given that the water tank has a diameter of $D_0$ and a hight $H$. The water outlet is ...
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2answers
91 views

Is Torricelli's law “wrong” for big holes? - Tank draining problem

Consider a tank full of water with a constant cross-sectional area A1 placed vertically on the ground. Now someone drills a hole of an area A2 in the bottom of the tank, and the liquid starts escaping ...
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1answer
35 views

Applying unsteady Bernoulli (to a balloon attached to a tube)

Using Bernoulli’s equation for an unsteady irrotational motion of an inviscid incompressible fluid, solve the following: Water of density $\rho$ is driven through a horizontal tube of length $L$ and ...
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0answers
66 views

Solve unsteady state Bernoulli equation for flow in a pipe

I am an engineer studying an unsteady-state flow through a pipe. The Pipeline has been cleanly cut into two halves, without deforming the cylindrical form of the pipe, exposing the contents to ...
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1answer
60 views

Why does Bernoulli's principle work?

So, if we have a large pipe which is constricted in the middle, the fluid in the middle section will move faster. Why is it so? What dictates that liquid that an X amount of it must pass on the other ...
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1answer
38 views

about venturi/bernuolli- what amount of pressure do I need to lift x amount of water? [closed]

I'm trying to build a venturi pump/tee in which I want air to create a suction which lift a liquid (like they do in paint sprayers), lets say water. My question is basically what is the minimal PSI ...
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1answer
55 views

How to derive velocity pressure in English units?

I know that velocity pressure can be calculated from dynamic pressure according to the potential energy of pressure (from Bernoulli's equation): $$ P = \frac{1}{2} \rho \overline{V}^2 $$ where P = ...
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3answers
173 views

Distance traveled by a water jet

I helped my kid in a science fair project, where we punctured holes in a water bottle at various heights and then measured the distance traveled by the water jets before they hit the ground. The ...
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2answers
68 views

Do rotating non-circular projectiles also experience Magnus lift?

The Magnus effect has been studied on spherical projectiles such as golf balls, tennis balls, and soccer balls. The backspin of a golf ball leads to Magnus lift that opposes gravity, thus allowing the ...
2
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2answers
132 views

Backwards airflow in a Venturi tube

When air is flowing through a Venturi tube, it's speed increases at the narrow section. If the airflow is arranged by moving the Venturi tube through calm air, this means air will momentarily flow ...
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3answers
152 views

Why does it seem as if big vehicles “attract” mine when I drive close to them?

When I drive a car at high speed and when I am near to another big car (like a van, or transport vehicle) I feel an attraction to or something push me toward the other big car. What's the physics in ...
3
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2answers
235 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 ...
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2answers
44 views

Microscopic definition of dynamic pressure of fluids

So we have a moving fluid and we know from Bernouli's equation that there is a term called dynamic pressure(not to be confused with the hydrostatic pressure of the fluid). So,what exactly is it and ...
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1answer
53 views

What is the difference between high speed water supply and high pressure water supply coming out of a hose?

According to Bernoulli's principle, $P + \frac{1}{2} d v^2 + dgh = constant$ where, P is pressure, d is density of water, v is velocity and h is height. Assuming that height of a plastic pipe is ...
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1answer
28 views

Liquid Flow Over Object

When there is a large object in the bottom of the ocean of height h, the surface of the ocean rises by a height less than h. In fact, if the ocean depth >> h, then the surface will rise negligibly. ...
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1answer
44 views

How can Bernoullis be solved without Vectors [duplicate]

Some time ago I asked a question why Dynamic pressure is considered scalar. Why is the dynamic pressure not a vector quantity? This still puzzles me so I hope to give a scenario that doesn't make ...
0
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1answer
37 views

Tank draining with piston

I am trying to solve a problem which is close to the tank draining (as here Fuel tank draining) but with a piston a the top of the tank which means $p_A$ different of $p_B$. I search the velocity ...
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3answers
1k views

What is basically the difference between static pressure and dynamic pressure?

What is basically the difference between static pressure and dynamic pressure? While studying Bernoulli's theorem, I came before these terms. The law says: When the fluid flows through a small ...
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1answer
377 views

Application of Bernoulli's theorem

My teacher told me the following examples of Bernoulli's principle. I didn't understand how Bernoulli's principle is applied in these examples. It is dangerous to stand on edge of platform when ...
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1answer
34 views

Does using Bernoulli's equation for a region of zero mean flow violate mass conservation?

Let's say I have a pressure reservoir with zero mean flow connected to a pipe with mean flow. So for the reservoir we have $p_1>0$ and $v_1=0$. For the pipe we have $p_2,v_2>0.$ Bernoulli's ...
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1answer
180 views

Equilibrium between two water tanks

I've been reading about hydrostatic theory, however I couldn't find a similar case/exercise about my basic problem. I have two water tanks (same size) filled with different water heights, and ...
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1answer
93 views

Find the discharge Q. Pipe flows [closed]

Trying to work my way through an example in my course notes on fluid flow in pipes and I'm really stuck on where to start. The question is as follows; A pipeline 10km long and 300mm diameter with a ...
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1answer
158 views

Compute pipe restriction from water flow and static pressure

How can I determine if residential water pipes have a restriction given, for example, flow rate and static pressure? Details: (1) You hook up a static pressure gage to a faucet which is in the ...
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1answer
115 views

The Bernoulli equation: positive and negative sign problem

According to bernoulli equation $$ P_1+1/2 \rho v_1^2+ \gamma h_1= P_2+1/2 \rho v_2^2+ \gamma h_2. $$ Because $$ v_1=0\quad h_1=0 $$ So $$ 0= 1/2 \rho V^2+ \gamma h. $$ It is wrong I know, but ...
3
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1answer
205 views

Is the change in cochlear potentials dependent on perilymph velocity? [closed]

context: This question may appear to be off topic because it is about the biological particulars of the human ear. Physics can solve abstract models inspired by living organisms, but it is biology ...
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0answers
23 views

Would a solid inside of a parcel moving due to buoyancy be affected by Bernoulli's Principle?

If a parcel (or column) of hot air were rising due to buoyancy and an extremely light solid were to be inside of this parcel (rising with it), would Bernoulli's effect cause the solid to stay inside ...
4
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1answer
390 views

Fuel tank draining [closed]

A cylindrical fuel tank is being drained from the bottom as in this picture : Conservation of flow rate : $v_A = \frac{S_B}{S_A}v_B = \alpha v_B$ Assuming that $z_B = 0$, Bernoulli's theorem ...
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1answer
247 views

Why is the dynamic pressure not a vector quantity? [duplicate]

I understand that static pressure is a scalar quantity as it acts equally in all directions, then by the same reasoning dynamic pressure should be a vector quantity as it only can be measured by ...
0
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1answer
43 views

Calculating velocity from a pressure distribution

Using computational fluid dynamics I have calculated the pressure distribution over a streamlined body. I have access to the static, dynamic and total pressure seperately and assume that I can use ...
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1answer
205 views

Intuitive meaning of a special case of the Bernoulli equation

In the Bernoulli equation, if $h$ equals zero, it reduces to $$P_1+\frac12\rho v_1^2 = P_2+\frac12\rho v_2^2$$ The equation does not have an intuitive meaning other than the fact that it is a bare ...
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40 views

Airfield Windsock

Why don't windsocks collapse? It would seem Bernouilli would say otherwise. But we know empirically that they don't. Proof:Visit any airfield. So the air in the sock must be going slower right? I ...
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1answer
150 views

Bernoulli's equation for flow between cylinders

Let's consider the situation bellow noting that the water cylinders aren't equal and there will be water flowing to the right (As indicated by the arrow) Taking Bernoulli's equation at the tip of ...
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0answers
409 views

Pressure required on a wing to lift a plane and the speed required to create this pressure difference [closed]

An aircraft has a single wing with a total area of A =1 2.6 m2 (assume that the thickness of the wing is negligible). When in motion, the air flows under the wing at the velocity that the aircraft ...
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1answer
160 views

Bernoulli Equation Paradox

Imagine a funnel with an extremely wide mouth, filled with water. Attached to the stem is a water pump that pumps water upwards (into the funnel). Water is being pumped in at the rate of Q. The cross ...
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4answers
500 views

Is a causal relationship implied by Newton's 2nd Law?

Throughout my time learning physics I have been imbued with the notion that forces cause accelerations, period. Accelerations don't cause forces, and they aren't merely correlated phenomena. By ...
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2answers
174 views

Definition of pressure in Bernoulli's principle

I have a difficulty to understand Bernoulli's Principle which states increased fluid speed decreases the pressure. But in a wind tunnel when we measure the pressure with a pitot tube, both the ...
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1answer
296 views

Problem understanding basic sail mechanics

I am trying to understand the physics behind a single sailed boat. I have read the following questions Sailing against the wind. Is this a fair model? What exactly is the 'lift' of a ...
2
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1answer
237 views

Feynman's derivation of Bernoulli (part of it)

OK, so what's up with the $\Delta M$ here? I don't get it. In fact, my textbook doesn't even put it in. I don't think it is a type-o because he continues on with the explanation. If anything I got ...
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0answers
112 views

Bernoulli's equation

So there's a pipe filled with water that has 4 other pipes with same radii connected to it. The question is to arrange heights from the smallest to the biggest level in it. $A_1$ and $A_2$ are ...
0
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2answers
276 views

Pressure $p$ in the Bernoulli equation

I know the Bernoulli equation that states that the energy along a streamline is constant: $$ \frac{v^{2}}{2}+gh+\frac{p}{\rho}=C $$ However I can't seem to figure out what exactly $p$ is in this ...
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1answer
208 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 ...
2
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2answers
473 views

Can the lift generated by a helicopter be justified using Bernoulli theorem? [duplicate]

When the shaft of the helicopter rotates, it creates a low pressure. Because of the low pressure, the helicopter lifts. Is my understanding that this is just an application of Bernoulli's theorem?
5
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1answer
381 views

Pipe in a flowing river problem

I'm working on a certain problem in fluid mechanics, which isn't really my strongest area. The problem is as follows: Curved pipe is partially submerged in a flowing river so that one end is pointing ...
2
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2answers
96 views

Air pressure in closed (circular) tube

I have learned that for fluids and gases $P_\text{total}=P_\text{dynamic} + P_\text{static}$. Suppose we have a closed circular tube in a form of ring filled with air under some pressure. In this ...
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1answer
237 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 ...
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1answer
1k views

Problem with Velocity of efflux [closed]

I am stuck in this problem- I need to find the velocity of efflux at the hole of the container. [We can assume that the area of the hole is negligible in comparison with the base area of the ...
3
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2answers
2k views

What exactly is the 'lift' of a sailboat as explained by Bernoulli principle

I have heard that when a sailboat is sailing against the wind, it operates on the principle of 'lift'. I am unable to understand the explanation, based on Bernoulli principle, completely. My question ...
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3answers
946 views

A question on Bernoulli's principle

Which is more appropriate regarding Bernoulli's principle fast moving air causes low pressure or lower pressure causes fast moving air.