Questions tagged [vortex]

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129
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12answers
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Why does my tea periodically alternate its rotational speed after stirring? (Link to video below)

I noticed that after stirring, a bubble in the centre of my mug of tea changed the speed it was rotating at periodically. Speeding up, then slowing down, then speeding up again, etc. Almost like when ...
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0answers
60 views

What causes vortices at the billiard ball particle level?

In a fluid/gas model consisting of billiard ball hard particle collisions what are the key behaviours that are needed to manifest the larger scale vortices? I can only seem to find descriptions of ...
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1answer
35 views

Rotational, Potential Flow

The short answer is "by definition, potential flow is irrotational", but please hear me out. I was working through "Fundamentals of Aerodynamics" by Anderson, and I noticed the following when he ...
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0answers
18 views

Velocity potential of an irrotational vortex

I would like to investigate the isolines of a two-dimensional velocity potential of an irrotational vortex defined using polar coordinates as $v=\frac{K}{r}$. I understand that the velocity ...
5
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0answers
190 views

An interesting observation: Ordered, up and down movement of vortex rings in water

I was watching a video on David Tong's research work when I stumbled upon a peculiar movement of vortex rings in water. Around the 1:20 time mark, Baths and Quarks: Solitons explained, David Tong uses ...
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0answers
20 views

Please help me to solve this question [duplicate]

Question on viscosity Help me clear my doubt
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1answer
40 views

How do the vortices in vortex-induced vibrations (VIV) form?

I am currently doing a research project on the topic of the Vortex Bladeless technology in a technical college course. I have been researching VIV and the intuition behind this, but I am still ...
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0answers
33 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
36 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 ...
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0answers
24 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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0answers
35 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 ...
3
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1answer
84 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: $\...
6
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1answer
88 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 ...
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1answer
41 views

Is a typhoon/hurricane also affected by Magnus Effect?

We all know that typhoons move as they rotate.
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0answers
37 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^{...
3
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2answers
108 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 ...
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0answers
32 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 ...
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1answer
34 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 ...
4
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1answer
123 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 ...
3
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0answers
188 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
64 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 ...
1
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1answer
65 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 ...
3
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1answer
95 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 ...
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2answers
84 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 ...
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1answer
46 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
26 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 ...
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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
94 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 ...
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0answers
65 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
77 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
4
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2answers
344 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
428 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
46 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
57 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 ...
2
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0answers
142 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 ...
2
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1answer
79 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?
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1answer
136 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 $. (...
4
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0answers
127 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 ...
1
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1answer
41 views

Is it possible to convert high rotational speed air vortices into high speed quasi-laminar airflow and how to do it?

I am no expert on the fluid mechanics field, but I am interested in generating high rotational speed vortices for my little research project. I believe that if a high speed airflow coming out from a ...
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2answers
116 views

vortex anti-vortex configuration to ground state [closed]

i'm studying kosterlitz transition. I'm reading this: https://assets.nobelprize.org/uploads/2018/06/advanced-physicsprize2016-1.pdf?_ga=2.51324009.1302372948.1538119052-1605759177.1538119052 Now ...
2
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1answer
544 views

Vortex anti-vortex?

i'm studying Kosterlitz THouless transition and i have a doubt: what is a vortex anti-vortex configuration? Is this thing? or this one I think that they are quite different !
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1answer
641 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?
2
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2answers
107 views

Why do cyclones have translational motion?

This answer provides a good explanation why cyclones (e.g. hurricanes, typhoons, and tornadoes) have rotary motion. However, cyclones usually also have translational motion -- they move from place to ...
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1answer
57 views

Proof regarding curl of a vector [closed]

I'm stuck in this problem where we need to prove that the curl of the velocity vector is twice the angular velocity of a rigid body in circular motion. How do I prove it? I am very new to the concepts ...
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2answers
3k views

Can a water vortex (whirlpool) be used to efficiently store energy?

Either a large, constrained cylinder of water or a large volume of open water (perhaps in the ocean) could be persuaded to form a vortex by pumping energy in. The body of water would be acting as a ...
3
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0answers
48 views

Good resource to “deduce” bathtub vorticies from navier stokes?

I am a mathematician that is interested in how physicists justify the creation and persistence of vortices (such as bathtub vortex or tornados) from Navier Stokes. The explicit solutions I have come ...
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1answer
230 views

Circular flow in a bowl

Let us assume we have circular flow in a bowl or a tea cup. (1) If the velocity of the fluid in the bowl is low, we have laminar flow. (2) However, to my understanding turbulent flow is defined as ...
2
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0answers
19 views

Is it possible to have a vortex with more than one attachment point?

In my study of two vortexes, fire whirls and tornadoes, I have come to hear a bit about vortex attachment. As far as I can understand, a vortex is attached to its "power source" for lack of a better ...
1
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1answer
31 views

Paired states in condensed matter systems

In condensed matter systems we can have paired quantum states, for instance vortex-antivortex pairs and Cooper pairs, etc. How do the partners within each pair recognize each other and stay together (...

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