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Questions tagged [vortex]

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Navier Stokes equations - Tornado Vortex Simulation

I am trying to understand how the navier-stokes equations are used in order to describe a vortex. I know that you must define the boundary conditions(although I don't know what these conditions are) ...
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45 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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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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Schlichting vortices

I have been told that there are vortices which occur during specific oscillations in cavity. The name of the phenomenon is vortices of Schlichting. I looked up many sources on the Internet and only ...
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1answer
75 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
34 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
27 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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61 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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0answers
47 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
96 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
32 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
68 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
147 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
164 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
80 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
51 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
2k 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 ...
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0answers
38 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
160 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
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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
38 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 ...
3
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1answer
61 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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0answers
129 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 ...
2
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1answer
47 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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0answers
47 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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0answers
124 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 ...
1
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1answer
62 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
179 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
65 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. ...
2
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1answer
50 views

Superfluidity: separation of quantised vortices in a vortex tangle

It is often quoted (see https://doi.org/10.1016/j.piutam.2013.09.008) that the separation $\delta$ between quantised vortices in a vortex tangle in a superfluid is approximately $$\delta \approx L^{-...
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1answer
141 views

Smoke ring in space?

I understand that a smoke ring is an example of a vortex. I sort of grasp why a vortex stays coherent - the rotary motion of component molecules cause a pressure difference within the vortex. I do ...
2
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1answer
344 views

Are all Irrotational Flows Frictionless and Laminar?

A I understand, Irrotational flows are also inviscid (have zero viscosity). This would lead me to assume that these kind of (purely fictional) flows would be well ordered (Laminar) and be frictionless....
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0answers
47 views

Most effective vortex shape

What shape would produce the fastest velocity of the fluid near the center and bottom of the vortex - an axially symmetrical paraboloid or a nautilus inspired spiral paraboliod? If the latter, how ...
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1answer
291 views

Vorticity of a velocity field in cylindrical coordinates [closed]

I'm currently working on a obtaining the vorticity of my velocity field $u_r, u_\theta, u_x$. I know that this is equal to the curl of the velocity field $\nabla \times u$: $$\nabla \times u = \frac{...
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0answers
49 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 ...
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1answer
337 views

How to understand rotation and Stokes' theorem?

In my electromagnetic fields course, we discussed Stokes' theorem and how to unterstand the rotation of a vector field. Therefore, my professor showed us the following image (I stole it from the ...
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0answers
47 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 ...
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0answers
52 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 ...
0
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1answer
47 views

Conservation equations in a vortex

I have compared several models of vortex with experimental measurements considering only azimuthal velocity. So now, I would like to check if the conservation equations are satisfied at every point. ...
2
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2answers
44 views

Violation of Derrick's theorem for finite energy, time independent solutions?

How are vortices the finite energy time independent solutions for 2+1 dimensions abelian higgs model? Doesn't it violate derricks theorem that there are no finite energy time independent solutions in ...
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0answers
56 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
42 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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3answers
844 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 ...
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0answers
73 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), ...
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0answers
97 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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1answer
49 views

What makes air to spin?

The phenomenon is observed in tornadoes where the air spins with a great speed causing so much damage. Can there be any experiment that can be performed to make the air spin in clockwise or ...