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Questions tagged [vortex]

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12
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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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0answers
146 views

Do the Shallow Water Equations produce 2d vorticity/eddies? Why/Why not?

My understanding so far: given a small flow moving forward within a larger stationary body of water, the water ahead would pile up, creating hydrostatic pressure in all 2d directions (and thus ...
4
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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 ...
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0answers
228 views

relation of vortex street structure to Stroudhal & Reynolds Numbers

While on an expedition to a lake, it was noticed that the wind speeds gusted violently in seemingly periodic wakes and the proposed explanation was Von Karman vortex shedding off of nearby mountains ...
3
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1answer
92 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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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
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 ...
3
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0answers
88 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 ...
3
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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
3
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0answers
44 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 ...
3
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0answers
214 views

What is the relationship between the angular speed and the diameter of the eye of a water vortex?

In a water vortex formed in a plastic bottle, what is the relationship between the angular speed of the water and the diameter of the hole in the cap? I would have expected that according to the ...
2
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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 ...
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?
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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 ...
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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 ...
2
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164 views

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 ...
2
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0answers
62 views

Cascade vs Inverse Cascade: Energy flow in 2D and 3D turbulence

We know that vortices tend to coalesce in 2D(inverse cascade) as opposed to 3D where they 'break down' into smaller vortices(cascade) ie. energy flows fro larger to smaller scales in 3D and opposite ...
2
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0answers
77 views

Why is the seperation of a tight pair of vortices a Topological Phase Transition?

I have been doing some research on Topology in Physics and so I came across this picture Source is this link. Now the way I understood Topology so far is that you can classify specific ...
2
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0answers
119 views

Why is it said that vorticity gets produced at a wall?

I am currently taking a fluids mechanics class and during the lecture the Prof. explained the following: when dealing with a 2D incompressible newtonian flow without external forces (gravity), ...
2
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0answers
558 views

Vorticity generation behind curved shock waves

The generation of a curved shock wave can take place in many applications. For instance, with high speed blunt bodies, the bow shock in front of the body will display a general curvature. Below is an ...
2
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0answers
232 views

order of BKT phase transition

What is the order of the BKT phase transition (first or second), that is the phase transition in 2d in which thermal vortices destroy any order in the system. How is this connected to the "universal ...
2
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0answers
54 views

Why do vortices scatter at right-angles

I have been taking a course on non-perturbative physics and currently the teacher is away so I cannot ask him. In the lectures, he made the claim that a pair of vortices in the abelian-Higgs model ...
2
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0answers
124 views

The Optics of the Vortex (in Water): why there is a bright ring also in reversed flow?

This question is closely related to this one; The optics of vortex (in water): why there is a bright ring? In this case "physics girl" gives somehow an plausible explanation, and it's only debatable ...
2
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0answers
55 views

Formation of vortices in superconductors

So I'm trying to understand how mixed state of a type II superconductor becomes the energetically favourable state. I've been through a simple approximate calculation considering a S-N boundary to ...
2
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0answers
89 views

Why are quantum vortices so large?

Quantum vortices in helium are almost macroscopic, and can be be imaged in a light microscope: http://www.aps.org/units/dfd/pressroom/papers/gaff09.cfm How can vorticity be quantized on such a large ...
2
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1answer
157 views

Vortex shedding

So I was reading about vortex shedding, and got to know that it causes the building to resonate. Is there any way to use this resonance to generate electricity (maybe use quartz?) I am trying to make ...
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30 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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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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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
35 views

Is a typhoon/hurricane also affected by Magnus Effect?

We all know that typhoons move as they rotate.
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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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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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60 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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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?
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227 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 ...
1
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1answer
81 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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0answers
58 views

Thought experiment with conservation laws 1

So, imagine you have the following situation for two viscous fluids under a gravity field. Let's consider the walls and the fluid surface as our isolated system $\Omega$ (neither mass nor energy ...
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0answers
71 views

Why is the kinetic helicity of a fluid important?

In fluid dynamics, the kinetic helicity is a measure of the degree of knottedness and/or linkage of the vortex lines of the flow. It's a conserved and topological quantity. It has no effect on the ...
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0answers
44 views

How is this equation obtained?

I'm trying to code a script to solve aerodynamics problems with different numerical methods. I'm analyzing one method, in which I'm particularly stuck because I need to obtain a velocity equation, but ...
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0answers
157 views

Why are geodesic congruences irrotational?

In Sean Carroll's GR book "Spacetime and Geometry", in Appendix F on geodesic congruences, he defines a (timelike) geodesic congruence as the integral curves vector field so that: $$U_\mu U_\mu = -1$$...
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0answers
88 views

Is there an Okubo-Weiss function for axisymmetric flows

I have recently learned about the Okubo-Weiss criterion in a ($x,y$) and a ($r,\theta$) coordinate system. Is it possible to recast this criterium in an ($z,r$) system, that is for axisymmetric ...
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0answers
24 views

Is the rotational velocity of a vortex consistent across its height?

I am trying to locate information about calculating the rotational velocity of a vortex. Is the velocity at the vertex maintained across the entire vertical height of the vortex? As the radius ...
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0answers
69 views

What is the singularity of a bathtub whirl?

I have read that at the center of a bathtub whirl the velocity should be infinite and that is a singularity. Could someone explain this and the mechanism that viscosity counteracts this infinite ...
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0answers
105 views

Optical distortion caused by a vortex: “gravitational lensing” in a swimming pool?

Falaco solitons were accidentally discovered by professor R. M. Kiehn while he was visiting a friend's swimming pool. He describes them as [...] a pair of globally stabilized rotational ...
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0answers
201 views

How to define a vortex core without first defining a vortex?

A common definition of a vortex is that proposed by Robinson 1991 : A vortex exists when instantaneous streamlines mapped onto a plane normal to the vortex core exhibits a roughly circular or ...
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0answers
132 views

What is vortex row image system in fluid mechanics?

What is vortex row image system in fluid mechanics? I have lot search but I did not find any best answer about this question. Please explain about this topic or give me best link of book or site.
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273 views

Mathematical understanding of vortex solitons

I am wondering if anyone has ever come up with a mathematical description of something that (to me, and I am no expert) look like soliton vortexes. The example I can think of is if you create two ...
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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
53 views

Sustained nuclear criticality in liquid vortex

In 1958, chemical operator Cecil Kelley was killed by a nuclear excursion in a mixing tank. A tank intended to reprocess trace amounts of dissolved plutonium-239 accidentally had dramatically more ...
1
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1answer
87 views

What is beam confinement?

In the context of the propagation of an electromagnetic wave and optical vortex solitons, I came across the term "beam confinement". Particularly, beam confinement requires the amplitude of the ...