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Questions tagged [vortex]

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0answers
29 views

Vortex chamber for maximum vacuum at given pressure difference?

Suppose we have a cylindrical vortex chamber with one exit pipe at the top. ( like here: https://ars.els-cdn.com/content/image/1-s2.0-S092188311830520X-gr2.jpg ) The air comes inside through the ...
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0answers
32 views

Why does the cold air coming down from an ice cream oscillate?

It occurred to me that when I held a choc-ice the other day (a wooden paddle with a chocolate ice-cream above it with two large smooth sides) that I could occasionally feel cold air falling down onto ...
3
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1answer
94 views

Red colour of the Great Red Spot

In Wikipedia it is mentioned: "It is not known exactly what causes the Great Red Spot's reddish color. Hypotheses supported by laboratory experiments suppose that the color may be caused by ...
3
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1answer
53 views

Is a hole better for ceating a toroidal vortex than a pipe?

Does a hole work better for creating a toroidal vortex, where the fluid starts to turn as it exits, than a pipe, where the flow inside is more laminar. Some high power vortex guns have a cone shaped ...
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7answers
4k views

Vortex in liquid collects particles in center

At xmas, I had a cup of tea with some debris at the bottom from the leaves. With less than an inch of tea left, I'd shake the cup to get a little vortex going, then stop shaking and watch it spin. ...
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0answers
23 views

Superfluid Vortex Lines Bifurcation and Winding Numbers

Vortex lines in superfluids are characterized by their quantised circulation: $k = \frac{h}{m}\times n$, where $n$ is the winding number in the sense of a topological winding number. Now, most vortex ...
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2answers
312 views

Why did David Tong say that the global topological $U(1)$ symmetry is unbroken in Higgs phase?

In the paper A Duality Web in 2+1 Dimensions and Condensed Matter Physics by Seiberg, Senthil, Wang, and Witten, they studied the particle-vortex dualities in $2+1$ dimensions. On page 20, section 3....
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1answer
278 views

Recommended books about vorticity

Could anyone suggest a good introductory book or any online resource about vorticity? I just now started to learn physics but I have a good mathematical background.
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1answer
227 views

Vortex in a Pipe / Solutions or approximations?

I want to study a vortex flow in a pipe; in other words helical flow. A couple introductory texts on fluid mechanics (e.g. Shames, Mechanics of Fluids) describe the solution to vortex flow in 2D: $...
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0answers
29 views

Vortex ring formation

I think I undersand how a vortex ring is formed when we use a long tube: Vorticity is "created" by the velocity gradient caused by the viscosity and then, when the gaz goes out, the Kelvin theorem ...
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1answer
560 views

How do speed and density change in a turbulent flow?

Suppose a fluid passes from having laminar flow, to having a turbulent flow (like when passing after an object). How do fluid speed and fluid density change after that?
3
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1answer
70 views

How does the $U(1)$ global symmetry break in the gauged $XY$ model?

I'm studying the particle vortex duality, and I'm confused how we're able to say that in the Coulomb phase, the "hidden" $U(1)$ global magnetic symmetry spontaneously breaks. gauged XY model: $\...
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2answers
971 views

Why do you feel air moving past you when you walk?

I know that when you walk through the air you form a wake vortex and turbulent air behind and the vortex grows the faster you walk. When I walk past people I almost feel wind that's behind them. So ...
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1answer
77 views

Why does a vortex last so long?

Yesterday I saw vortex shed from a kayak paddle around 40 yards behind the person paddling so it had been rotating for over a minute. Why isn’t the energy in this vortex dissipated quickly, e.g. why ...
12
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1answer
353 views

Why are superfluid vortex lattices stable?

Both (a) neutral superfluids that are externally rotated, and (b) type-II superconductors (i.e. charged superfluids) under applied magnetic fields between the critical fields $h_{c1}$ and $h_{c2}$, ...
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1answer
35 views

Is a typhoon/hurricane also affected by Magnus Effect?

We all know that typhoons move as they rotate.
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2answers
68 views

What is irrotational flow? How to judge?

For example, when the wing moves horizontally, the direction of fluid flow changes first to upward at the leading edge of the wing and then to downward at the trailing edge. Does it rotate? If the ...
3
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1answer
770 views

Do communicating vessels work when water is moving?

I want to know if the water level equalize in communicating vessels, when in one of the vessels there is a vortex, or any other water movement, and if the level does equalize, what will be the level? ...
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0answers
34 views

Vorticity of Fourier Expanded Velocity

I have been reading some papers which find all three components of the vorticity vector for a Fourier expanded (perturbation) velocity field i.e $\mathbf{u'}(x,y,z,t)=\int\mathbf{\hat{u}}(x,y,t)e^{...
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0answers
28 views

Vorticity - Rankine vortex: how can we say that $\frac{\partial u_\phi}{\partial z} = 0$

\subsection{a} A Vortex formed in a bathtub, tornado or in other real world scenarios, exhibit nearly a solid body rotation in the core while far away from the center the flow is irrotational. This ...
6
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1answer
438 views

What's the corresponding symmetry of enstrophy conservation?

In fluid mechanics, especially 2D turbulence study, people talk about conservation of enstrophy. But I can't really understand enstrophy very well, and what's the corresponding symmetry of enstrophy ...
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1answer
30 views

The Energy Spectrum of Bound states in the Vortex Core of Type II Superconductors

In the calculation of the so-called Caroli-de Gennes energy states in a type II superconductor the following Bogoliubov-de Gennes Hamiltonian is used: $$ H=- (\frac{1}{2m}(\nabla+ie\mathbf{A}\sigma_z)^...
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0answers
39 views

Does linearly accelerating a swirling liquid slow down its angular motion?

Say you pour some freshly brewed coffee in your favourite mug and give it a nice stir. As you depart for your desk, does the (approx) linear acceleration you apply to the mug slow the coffee's overall ...
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0answers
185 views

What's the origin of the vortex's ansatz $\phi\big(\vec{x}\big)=f\big(r\big)e^{-in\theta}$?

What's the origin of the vortex's ansatz $\phi\big(\vec{x}\big)=f\big(r\big)e^{-in\theta}$ in the de Vega and Schaposnik paper? In their article Classical vortex solution of the Abelian Higgs model,...
3
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1answer
91 views

Charge-Vortex Duality for Bosons

Consider a (2+1)d continuum field theory with the Minkowski action $$\mathcal{L}=|\partial\phi|^2-r|\phi|^2-u|\phi|^4,$$ where $\phi$ is a complex field. The theory undergoes a quantum phase ...
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3answers
229 views

Total vorticity generation in 3D

In 2D flows, the total vorticity generation for an impulsively started plate can be found by measuring the circulation of the flow. This gives the vorticity generated per unit length. I would like ...
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2answers
268 views

Calculation of Berry's phase due to monopole tunneling event of $O(3)$ NLSM on square lattice

I am currently reading the seminal paper by Duncan Haldane: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.61.1029 In this paper, he asserts that for a unit-vector field $\hat{\Omega}(x,y,t)...
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9answers
19k views

Why there's a whirl when you drain the bathtub?

At first I thought it's because of Coriolis, but then someone told me that at the bathtub scale that's not the predominant force in this phenomenon.
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4answers
1k views

Why does bathwater make a vortex in the plughole?

When I google for this I just get stuff about whether or not the Coriolis effect makes it go clockwise or anticlockwise, but I don't care which direction it turns in. I want to know why it turns at ...
2
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1answer
75 views

How can a vortex be created?

i have seen this video. https://www.youtube.com/watch?v=pnbJEg9r1o8&t=96s It is not completly clear how a difference of velocity can cause a vortex, can you explain me?
6
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1answer
176 views

Do vortex tubes work with a reversed end plug?

Would a vortex tube still work if instead of a cone plugged into the 'hot' end you had a smaller hole on the 'cold' end? As I understand it, the point of the cone on the hot end is to only allow the ...
1
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1answer
51 views

How to calculate vortex shed frequency curve, versus speed of the incident current

I have a current of air that hits a cylinder, and an hot-wire probe is measuring the velocity behind the cylinder. I have an array of measured velocity and a frequency. How do I get the vortex shed ...
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3answers
2k views

Whirlpools and Tornados

This may not be a great question. But whenever you drain water, a small whirlpool happens, obviously. This got me thinking... Can we model tornados with this effect, would it even be beneficial?
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2answers
60 views

Vortex tube without compressed air

I am looking for an apparatus to cool/heat air without moving parts and using only a pressure source. From this, I came to a "vortex tube". However, all practical implementations are based on ...
1
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1answer
43 views

What is the mechanism behind bathtub whirl?

I understand that at the middle of the whirl can't be any water because that would make the velocity of water infinite. But what is the mechanism, the force, the structure that removes water from the ...
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0answers
25 views

Increased Stability of Vortex Rings by Pushing it

I've noticed in playing around with smoke rings that they are substantially more stable in their axial motion if pushed from behind by a hand, as can be seen in various Youtube videos. I was wondering ...
4
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1answer
119 views

How many independent properties can a photon have?

Two recent papers about photon orbital angular momentum have set my head spinning as well. I'll try to define "property" as something you can change in one arm of a Mach-Zehnder interferometer, and "...
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0answers
27 views

Design of terminal cone on chimney to increase exit speed

A 1.5m diam chimney locally has been fitted with a 45degree cone in order to increase the exit velocity and thus project the pollution higher. It seems visually to have failed, can you direct me to ...
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0answers
177 views

Physics behind a blue “firenado”

In the NYTimes video Harnessing the Firenado, a rotating yellow sooty flame is suddenly transformed into a clean blue rotating flame. What is the physics behind this transformation? What is it about ...
3
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0answers
85 views

Fluid mechanics, symplectic structure, the Hamiltonian, and vorticity

Consider an inviscid irrotational fluid in two dimensions. There are some explicit connections with symplectic geometry that I do not understand. I am not well versed in the later topic, so please ...
4
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2answers
2k views

Why is the eye of a cyclone a forced vortex?

As far as I understand, a forced vortex has a velocity profile $u \propto r$ ($r$ is radial distance from centre of vortex), concluding at some outer boundary $r=R$ to avoid fluid particles ...
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0answers
59 views

Difference between von Karman vortex street & shedding

I want to know if there are any differences between von Kármán vortex street and vortex shedding ? If so, what are they?
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0answers
73 views

Vortex ring solutions in General Relativity

Vortex rings are captivating toroidal self-reinforcing fluid systems that can happen in turbulent fluids. I wonder if something similar can exist as a solution to Einstein's gravitational equations
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1answer
323 views

What is the physical meaning of irrotational flow?

I am studying fluid dynamics and while searching on the internet, found many videos explaining the mathematical aspect of rotational and irrotational flow, but i need more clarity on what actually it ...
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1answer
2k views

Vorticity and Shear - Irrotational and Rotational Vortex's

I have trouble understand how Vorticity occurs in a Rotational and not in a Irrotational vortex when I consider it in terms of shear forces. A Rotational vortex has a velocity profile where $v∝r$ ...
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1answer
44 views

Motion of a contrail “vortex”

I want to understand what causes this motion on contrails (Cirricular motion) and it’s name if possible. What effects it? How and why is it formed?
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1answer
49 views

Why that Bernoulli function contains many streamlines and vortex lines but not only singular streamlines?

I know that for a stream line inside the gradient part equal to a constant. But when we consider the fluid is rotational which the velocity cross product vorticity not equal to zero. So how can we ...
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0answers
134 views

At what critical Reynolds number does vortex shedding begin?

In: "Fluid Dynamics", Chapter 3 (Turbulence), Section 26, Landau and Lifchitz analyze the problem of the stability of a steady flow past a body of finite size. The fluid is assumed to be ...
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1answer
130 views

Vortex in superfluid?

I'm studying superfluid helium 4. I have studied that the superfluid has a velocity : $ \vec{v}_s = \frac{\hbar}{m} \vec{\nabla} \varphi(\vec{r}) $ $\rightarrow$ $ \nabla \times \vec{v}_s = 0 $. (...
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0answers
122 views

Why does type-I superconductor behave differently than type-II as $H$ is increased?

As one increases the external magnetic field $H$ above a critical value $H_c$, a type-I superconductor abruptly changes to a normal conductor. But for type-II, the transition is not sharp but gradual ...