The tag has no usage guidance.

learn more… | top users | synonyms

0
votes
0answers
10 views

Measuring Steam Flow with Venturi Effect?

I understand steam is a compressible fluid and that the Bernoulli effect has been generalised for compressible fluids but I'm struggling understand how the Venturi effect can be generalised to allow ...
1
vote
0answers
35 views

On deriving a fluid flow pressure drop model using either physical theory or empirical methods

I'm trying to derive a model from physical principles of fluid flow, a simple quadratic model that tends to well fit actual pressure-flow data. For (real) subsonic air flow (ideally adiabatic) ...
1
vote
1answer
68 views

Flow in diverging channel is unstable according to Bernoulli's equation

So let's say we have a circular pipe with a variable cross section with an inviscid incompressible fluid flowing through it. The areas of the two ends are $A_1$ and and $A_2$. Let's say we also ...
0
votes
0answers
17 views

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 ...
0
votes
1answer
41 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 ...
2
votes
1answer
54 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 ...
4
votes
2answers
161 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 ...
1
vote
1answer
46 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 ...
2
votes
1answer
136 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 ...
0
votes
2answers
102 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 ...
0
votes
1answer
67 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 ...
1
vote
1answer
121 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 = ...
2
votes
3answers
340 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 ...
1
vote
2answers
113 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
votes
2answers
217 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 ...
5
votes
3answers
169 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
votes
2answers
1k 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 ...
0
votes
2answers
67 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 ...
0
votes
1answer
85 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 ...
0
votes
1answer
30 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. ...
0
votes
1answer
45 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
votes
1answer
38 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 ...
2
votes
3answers
2k 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 ...
1
vote
1answer
606 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 ...
0
votes
1answer
35 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 ...
1
vote
1answer
238 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 ...
-1
votes
1answer
115 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 ...
1
vote
1answer
202 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 ...
0
votes
1answer
138 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
votes
1answer
217 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 ...
0
votes
0answers
24 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
votes
1answer
395 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 ...
2
votes
1answer
370 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
votes
1answer
45 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 ...
3
votes
1answer
222 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 ...
0
votes
0answers
45 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 ...
3
votes
1answer
165 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 ...
1
vote
0answers
489 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 ...
1
vote
1answer
178 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 ...
3
votes
4answers
536 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 ...
0
votes
2answers
191 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 ...
6
votes
2answers
362 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
votes
1answer
247 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 ...
1
vote
0answers
121 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
votes
2answers
317 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 ...
1
vote
1answer
227 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
votes
2answers
587 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
votes
1answer
413 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
votes
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 ...
0
votes
1answer
257 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 ...