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Questions tagged [vortex]

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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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27 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
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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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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
32 views

Is a typhoon/hurricane also affected by Magnus Effect?

We all know that typhoons move as they rotate.
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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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2answers
63 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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27 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
28 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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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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1answer
84 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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184 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,...
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1answer
52 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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1answer
47 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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1answer
60 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
58 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
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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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 ...
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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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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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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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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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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
273 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
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
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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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132 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
73 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
129 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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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 ...
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1answer
38 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
103 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 ...
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1answer
401 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
533 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?
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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
54 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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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 ...
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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
211 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 ...
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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 ...
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1answer
30 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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1answer
51 views

Vortex motion in superconductors

In mixed state of a type-II superconductor, when we allow a transport current to pass through it, we say that the Lorentz force acts and as a result the flux starts flowing, when the force is greater ...
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1answer
71 views

Why does this vortex bubble ring bounce off the surface of the water?

https://youtu.be/QascQV88FEI?t=2m56s Why does this vortex bubble ring reflect off the water-air boundary?
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223 views

Two vortex rings colliding (reasons and the number of rings created)

I recently saw an experiment in youtube (vortex collision experiment of 1992 recreated). I found it very impressive and I was wondering if someone can give me a brief explanation, since in the ...
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1answer
70 views

How to know whether electric field is rotating without divergence? (basic question)

Sorry for my broken English. I`m a physics undergrad and frankly know nothing about the subject yet. Today I was told by my professor that if electric field becomes weaker as it goes further from the ...
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53 views

Topological solitons in general dimension

Let's begin with a simple model of a field theory: $$ \mathcal{H} = \int ( \nabla \phi ) ^2 $$ where $\phi$ is an angle valued field defined on some space. We suppose for the moment to freeze out ...
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Topologically proctected twist in the wave function (TKNN invariant)

In the famous TKNN paper and subsequents the authors wisely argue that the transversal conductance in the Integer Quantum Hall Effect has a topological interpretation as the integral of the curvature ...
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1answer
78 views

Do whirlpools in water have the same rotation speed regardless of size?

I recently read that all flat disk galaxies have the same rotation speed regardless of mass and size, so I was wondering if this same feature was visible in any other similar rotation such as a ...
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204 views

Can I determine if the flow laminar or turbulent from the vorticity?

I made a 3D model and i get a numbers for the vorticity but i can't know if this numbers can used to determine if the flow is laminar or turbulent. and if yes what is the critical value of the ...
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1answer
168 views

Vortex solution to Differential Equation

I am looking for a differential equation whose solutions are what I call "open" vortices. These vortices are not closed in themselves, but sort of "absorb" the surrounding "fluid" and also "emit" it. ...