Questions tagged [vortex]

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Acceleration of fluid in a magnetohydrodynamics vortex

In the following video we see a mercury vortex done by magnetohydrodynamics: https://youtu.be/au4hbUm4mMo In the following manuscript they say that the fluid will accelerate according to (14) ${}^1$: ...
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Can I treat fluid a rigid body calculating Moment of inertia? If not, how would I calculate it?

I wanted to set out calculating how much moment of inertia a bottle of water had so as to see how fast a bottle had to spin to create a non-zero constant angular velocity in the water. As I understand,...
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2 votes
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Will two rotating disks in a fluid be 'attracted' to each other?

Imagine two rotating disks in a fluid like this drawing here: The rotating disks will create a rotating flow by friction in the fluid. The flow between the disks will be higher velocity than the ...
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How does gravity affect the formation of vortices?

Context: I understand the axis of vortices can form in any direction (like underwater used by fishes). However, in large vortices in water bodies, for example, in a closed water bottle, the centre of ...
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Why is the energy of a vortex in a superconductor finite?

I just had a glimpse of the Ginzburg-Landau theory of superconductivity. I am surprised that that the energy of a vortex is finite. This is surprising because as far as I know, in superfluids, the ...
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Bean model: Pinning force vs. magnetic? force

I am trying to study the Bean model, and as I understand, there are two forces at play. First, we apply an external field parallel to the surface, which varies in x. This causes a current density, and ...
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Why does my coffee spin the opposite way that I spin the cup?

I was just drinking a latte in a large cup, and when I spun the cup (doing that smooth one handed “mixing” thing that you usually see with a mixed drink or something) I noticed the design on and the ...
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Reference/source of the "derivation" of the magnetic force moment on anisotropic superconductor (type II)

I have been reading a diploma thesis of a fellow physics student and I have came across the following that was not referenced in any way (I want to read about it some more): The section starts... In ...
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What role do quantized vortices play from the Superfluid model in Superfluid Vacuum Theory?

When rotating a superfluid (such as $^{4}$He) below its critical temperature, sometimes quantized vortices pop up, depending how fast one rotates this superfluid. In the SVT model, they propose that ...
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3 votes
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Why do "quantum vortices" form in superfluids?

I've been reading up on Superfluids, and they've fascinated me. I understand why their superfluid component has zero viscosity, but there's one aspect that's bothering me, and that's the formation of ...
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Argument for flux quantization

I am reading P. Coleman's Introduction to many-body physics. Coleman claims that At large distances, energetics favor a reduction of the circulation to zero $$\lim_{R\rightarrow \infty}\omega=0$$ ...
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How can I compute the axis of rotation of a fluid vortex from the velocity field?

Let's say I have data on the velocity vector field of a fluid vortex such as e.g. a Hurricane available on a regular 2D grid. How can I compute the axis of rotation of the velocity vector field to ...
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How exactly do vortices generate sound and cause pressure fluctuations to produce sound waves?

I wish to understand qualitatively, how vortices generate sound by creating longitudinal sound waves? Vortices are often mentioned as the cause of sound production for things like corrugated whirly ...
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Is vortex physics key to understand the universe simulation hypothesis? [duplicate]

Seth Lloyd, US computer scientist and Professor of Mechanical Engineering and Physics at the renowned Massachusetts Institute of Technology (MIT) says that the universe itself is a giant quantum ...
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Kelvin's Circulation theorem

Recently, I dipped my spoon into my tea. I saw that as I dipped my spoon into my tea, two vortices formed at both edges of the spoon. I guess this is similar to vortices forming at the end of ...
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Surface tension between normal and superconductor phases

I am studying the phenomenological description of superconductors based on Tinkham's Introduction to Superconductivity. In Chapter 2.3.2. it discusses the difference between Type-1 and Type-2 ...
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Energy density of a cosmic string in the Abelian Higgs Model (Nielsen-Olesen Vortex)

my question is what the energy density of a cosmic string in the abelian higgs model is? I have different sources (Scholarpedia Cosmic Strings, the book "Cosmic Strings and Topological Defects&...
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Curved shocks and vorticity generation

In fluid dynamics, it is known that curved shocks (which are common, e.g., in bowshocks) generate vorticity. I am looking for a quantitative derivation.
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Is the Biot-Savart energy always a kinetic energy (vortex dynamics)?

I'm trying to understand the paper On Bubble Rings And Ink Chaldeliers from Padilla et al. (On Bubble Rings And Ink Chandeliers. Right now I'm reading section 3.3 Equations of motion. There, the ...
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Interpretation of $\frac{1}{r}\left(\frac{\partial V_\phi}{\partial x^\theta}-\frac{\partial V_\theta}{\partial x^\phi}\right)$ for given Space-time

I'm doing an exercise where I needed to find, for an arbitary $4$-vector $V^\mu$ $$ V_{r;\theta;\phi}-V_{r;\phi;\theta}=\ ???$$ for the space-time metric $$ ds^2=g_{\mu\nu}dx^{\mu}dx^{\nu}=\left(1-\...
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Conservation of Angular Momentum of an Inviscid Fluid

I was trying to prove that the angular momentum of an ideal MHD plasma, defined by $\vec{L} = \int \rho \vec{r} \times \vec{u} \ dV$ is conserved when there are no external torques. That is: $\frac{d\...
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What allows this tornado to form in a frying pan?

I have just seen this video here where a mini tornado has formed in a frying pan: https://www.youtube.com/watch?v=6CJ-8ze2FjE Does anyone know how this happens or where I can find an explanation?
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Could the rotating superfluid halo around a galaxy form a regular Abrikosov vortex lattice and serve as a naturally generated Quantum Matrix?

Spherical halo (shown in blue) surrounding galaxies could be a superfluid [Bose-Einstein condensate] according to Prof. Justin Khoury's hypothesis and may help to understand dark matter and galactic ...
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What is the difference between a skyrmion and a magnetic vortex?

Skyrmions and magnetic vortices are spin structures occurring in magnets. What are the differences between them? More specifically, I would like to understand their origin and how to distinguish them.
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What is the mechanism between whirlpools repelling and attracting each other?

I read somewhere that whirlpools in water will attract each other if they are spinning in opposite direction but will repell eachother if they are spinning in same direction. How does this exactly ...
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Vortex methods and Helmholtz theorem

I'm pretty new to vortex methods in fluid dynamics, I found in this paper (page 12, line2) that Helmholtz theorem states: that the dynamics of the vorticity field can be described by vortex elements, ...
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Is a vortex crystal a supersolid?

Reading the article [Rev. Mod. Phys. 84, 759 (2012)] by Prokof'ev and Boninsegni, a supersolid is defined as a homogeneous phase of matter in which both density long-range order (i.e. ordered spatial ...
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Rotation of liquid

How do we derive velocity of liquid in tube rotating about fixed axis? I've tried deriving but I can only think of equating centrifugal force and surface tension that pulls the liquid back.
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Why turbulent boundary layer is much thicker than laminar one?

boundary layer thickness is a function of molecular diffusion or vorticity diffusion within boundary layer along the plate. more vorticity diffusion(more spread out) give us thicker boundary layer but ...
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Combination of half wave plate, quarter wave plates and q-plate

I would like to understand half wave plate, quarter wave plates and q-plate. (A q-plate is an optical device which can generate light beams with orbital angular momentum of light (OAM)). Quarter-wave ...
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What causes Saturn's hexagon hurricane? [duplicate]

Recently, Tien Nguyen JPL Fellow - Chief Engineer at NASA Jet Propulsion Laboratory, did share this photo that says "Cassini catches an awesome glimpse of Saturn’s north pole hurricane" I ...
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Coriolis force at small scale

I would premit that I am not an expert (just an enthusiast) and my mathematical background is limited. That said I am trying to figure it out if the effect of coriolis force of big system (our planet ...
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If three vortices with circulations of $\Gamma_1$, $\Gamma_2$, $\Gamma_3$ respectively merge, what is the circulation of the final vortex?

Assuming an ideal fluid (ie no viscosity) would it be: $\Gamma_{final} = \Gamma_1 + \Gamma_2 + \Gamma_3$ ? What would happen if the fluid is not ideal?
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7 votes
2 answers
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Why are vortices stable?

Vortices persist over time, but change their shape. I am used to a structure that persists being “stable” as in it is robust against small perturbations. How can one define stability of a Vortex? For ...
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Optical Vortex Generation Using a Spiral Phase Plate (SPP)

I know it is possible to generate an optical vortex using a spp. The vortex will a have twist direction following the sign of its topological charge integer $\ell$. But how is the sign of $\ell$ ...
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Quantum vs Classical Vorticities

Excepting the circulation quantization, what are the differences between classical vorticities (created in classical fluids) and quantum vorticities (BEC superfluids)?
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How can vorticity tilt?

Most descriptions of tornado genesis make a reference to vorticity at the ground level with a horizontal axis somehow tilting to the vertical. Why doesn't this violate conservation of angular momentum?...
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Vortices in the effective field theory of Fractional Quantum Hall Effect

I am a grad student tasked with explaining what vortices are in the Zhang Hansson and Kivelson effective field theory of fractional quantum hall effect. I am explaining them to a final year bachelors ...
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Car: spiraling detail

Why do many car antennas have this spiraling detail and how does this relate to the noise level that a lawn mower emits? I will try to give an explanation, but I would like to know if my reasoning is ...
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2 votes
1 answer
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How does a velocity field (in a fluid) give rise to the gradient of a potential?

I'm trying to understand Ch. 3.2 of the paper On Bubble Rings and Ink Chandeliers by Padilla et al.: I don't understand how $u(\gamma', 0)$ gives rise to the gradient of a potential (last sentence on ...
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2 votes
1 answer
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Proving conserved quantities of $N$-vortices using Hamiltonian

I'm trying to prove the conserved quantities for $N$-vortices but having a difficult time doing so. I know it's something to do with Noether's theorem but not sure how to go about it. The Hamiltonian ...
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2 votes
1 answer
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Conserved quantities of $N$-vortices

In my notes we are given that for $N$-vortices with location ${(x_i,y_i)}^N_{i=1}$ and stegnth ${\Gamma _i}$. We have the conserved quanitites of energy, momentum and angular momentum. How does one ...
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Why do 2D hydrodynamic vortices merge?

Two point-like vortices with the same vorticity in 2D perfect fluid can rotate forever. Why do finite-sized vortices merge as soon as they touch? Why in general 2D fluid vortices of the same sign want ...
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How to describe the profile of a free vortex?

I was reading about free vortexes and came across this equation that describes the profile of a free vortex $z_{r}= z_{\infty} + \dfrac{k^2}{2gr^2}$ how do you get this relationship? I can't get the ...
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1 vote
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What Principles of Physics or Fluid Dynamics Explain Why Water Drains Slowly from a Funnel?

When I pour water into/through a funnel, it easily and quickly goes into a vortex flow and drains slowly. I can break the vortex to make it drain faster by redirecting the flow of water into the ...
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4 votes
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How to calculate the "vortex" correlation function in 2D free system?

I want to calculate the following correlation function in 2D square lattice: $$G(i, j, \tau) \equiv\left\langle e^{-\frac{i}{2}\left[\hat{\Phi}_{i}(\tau)-\hat{\Phi}_{j}(0)\right]}\right\rangle_{0}$$ $\...
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Which direction do whirlpools on a river eddy line spin?

In a turbulent flowing river, an eddy is created when water is forced upstream. The area where the upstream and downstream flows meet is called the "eddy line", and whirlpools often form ...
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1 answer
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Planetary vorticity vector calculus

The planetary vorticity is the vorticity due to the rotation of the planet. This should equal the Coriolis parameter. Let $\Omega$ be the angular velocity of the planet ($U_p$ the rotational velocity) ...
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Boundary conditions for radial solution of gauged topological vortices

I am following the book Topological Solitons by Manton and Sutcliffe and I am struggling to understand a boundary condition they choose to find the radial solutions of gauged vortices with finite ...
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2 votes
1 answer
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Chiral vortical effect (CVE) and gravitational anomaly

Chiral vortical effect is a generation of an axial current in the presence of the rotation. On the one hand, the expression for the $\mathbf{CVE}$ has the following form: $$ \vec{J}^{5} = \vec \Omega \...
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