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turbulenceteam
Registrace 30. 03. 2010
Visualization of a large-scale shear flow in 2D active nematic turbulence
Advective inertia is responsible for large-scale flow patterns, which, on sufficiently large domains, become visible as meta-stable condensates. Here, a large-scale shear flow forms. The chaotic motion of small vortex dipoles caused by topological defects in the orientation destabilizes the pattern. The visualization is obtained from a direct numerical simulation of the equations of motion with self-advection of the fluid flow.
For more details, see [add arXiv link].
For more details, see [add arXiv link].
zhlédnutí: 449
Video
Visualization of a large-scale vortex dipole in 2D active nematic turbulence
zhlédnutí 338Před 2 lety
Advective inertia is responsible for large-scale flow patterns, which, on sufficiently large domains, become visible as meta-stable condensates. Here, two opposing large-scale vortices form, similar to the ones in classical 2D turbulence. The chaotic motion of small vortex dipoles caused by topological defects in the orientation destabilizes the pattern. The visualization is obtained from a dir...
Visualization of inertial effects in 2D active nematic turbulence
zhlédnutí 215Před 2 lety
Left: The vorticity field in typical active nematic turbulence features small vortex dipoles (topological defects in the orientation) which move through the system chaotically. Center: Advective inertia causes the formation of large-scale flow, visible in the form of strongly moving vortex patches (red and blue). Right: Friction reduces this effect and restores a flow field similar to the one w...
Visualization of an initially circular material loop advected by a turbulent flow
zhlédnutí 490Před 3 lety
The twisting and folding action of the turbulent flow creates a complex loop geometry while the length of the loop increases exponentially on average. The visualization is obtained from a direct numerical simulation of fully developed turbulence. The material loop is composed of Lagrangian tracer particles which follow the flow. The exponential expansion of the line necessitates an adaptive ref...
3D Kolmogorov flow
zhlédnutí 597Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. This video shows the vorticity field of a three-dimensional Kolmogorov flow on an aspect-ratio-three domain, obtained from a pseudo-spectral simulation. Planes show out-of-plane vorticity averaged ove...
Generalized 3D Kolmogorov flow: effect of strong large-scale damping
zhlédnutí 229Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. We performed pseudo-spectral simulations of a turbulent three-dimensional Kolmogorov flow with large-scale damping on an aspect-ratio-three domain, which is driven by a sinusoidal shearing body force....
Generalized 3D Kolmogorov flow: effect of strong large-scale damping
zhlédnutí 253Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. We performed pseudo-spectral simulations of a turbulent three-dimensional Kolmogorov flow with large-scale damping on an aspect-ratio-three domain, which is driven by a sinusoidal shearing body force....
Generalized 3D Kolmogorov flow: effect of moderate large-scale damping
zhlédnutí 57Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. We performed pseudo-spectral simulations of a turbulent three-dimensional Kolmogorov flow with large-scale damping on an aspect-ratio-three domain, which is driven by a sinusoidal shearing body force....
Generalized 3D Kolmogorov flow: effect of weak large-scale damping
zhlédnutí 88Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. We performed pseudo-spectral simulations of a turbulent three-dimensional Kolmogorov flow with large-scale damping on an aspect-ratio-three domain, which is driven by a sinusoidal shearing body force....
3D Kolmogorov flow: evolution of z-averaged vorticity
zhlédnutí 150Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. We performed pseudo-spectral simulations of a turbulent three-dimensional Kolmogorov flow on an aspect-ratio-three domain, which is driven by a sinusoidal shearing body force. The visualization shows ...
3D Kolmogorov flow with large-scale damping
zhlédnutí 114Před 3 lety
Turbulent flows can be understood as the superposition of a mean flow, which evolves slowly and is shaped by boundaries or forcing mechanisms, and a multitude of chaotic, short-lived fluctuations. This video shows the vorticity field of a three-dimensional Kolmogorov flow with large-scale damping on an aspect-ratio-three domain, obtained from a pseudo-spectral simulation. Planes show out-of-pla...
Active vortex array in the marginal stability region
zhlédnutí 269Před 4 lety
Active fluids such as dense suspensions of bacteria or sperm cells show a variety of phases ranging from disordered turbulence-like states to well-ordered vortex arrays. Continuum theories for active fluids, which belong to the class of Toner-Tu models, can be used to study such phases as well as transitions between them. This video shows a time lapse of the the active matter system in the marg...
Emergence of an active vortex crystal
zhlédnutí 378Před 4 lety
Active fluids such as dense suspensions of bacteria or sperm cells show a variety of phases ranging from disordered turbulence-like states to well-ordered vortex arrays. Continuum theories for active fluids, which belong to the class of Toner-Tu models, can be used to study such phases as well as transitions between them. This video shows the emergence of an active vortex crystal (AVC) phase on...
Weakly excited phase in active fluid model
zhlédnutí 260Před 6 lety
Dense bacterial flows exhibit a turbulence-like phase, which has recently been modeled in terms of a generalized Navier-Stokes equation (Wensink et al., PNAS 2012). The video shows the vorticity field from a simulation of this model under weak excitation. The simulation was conducted by using a pseudospectral algorithm on a 2048x2048 grid. See arxiv.org/abs/1710.01956
Dynamic vortex lattice state in active fluid model
zhlédnutí 1,1KPřed 6 lety
Dynamic vortex lattice state in active fluid model
Square lattice state in active fluid model
zhlédnutí 360Před 6 lety
Square lattice state in active fluid model
Reconnection of vortex tubes in Eulerian and Lagrangian coordinates
zhlédnutí 464Před 6 lety
Reconnection of vortex tubes in Eulerian and Lagrangian coordinates
Merging of three vortices in Eulerian and Lagrangian coordinates in a 2D flow
zhlédnutí 2,7KPřed 6 lety
Merging of three vortices in Eulerian and Lagrangian coordinates in a 2D flow
Rayleigh-Benard Convection (two-dimensional and very turbulent)
zhlédnutí 58KPřed 10 lety
Rayleigh-Benard Convection (two-dimensional and very turbulent)
Turbulent Rayleigh-Bénard Convection in a Cylinder
zhlédnutí 3,2KPřed 12 lety
Turbulent Rayleigh-Bénard Convection in a Cylinder
Laminar Rayleigh-Bénard Convection in an Elliptical Cylinder
zhlédnutí 1,4KPřed 12 lety
Laminar Rayleigh-Bénard Convection in an Elliptical Cylinder
Laminar Rayleigh-Bénard Convection in a Rectangular Box
zhlédnutí 6KPřed 12 lety
Laminar Rayleigh-Bénard Convection in a Rectangular Box
Four Different Quantities in Turbulent Rayleigh-Bénard Convection
zhlédnutí 676Před 12 lety
Four Different Quantities in Turbulent Rayleigh-Bénard Convection
Temperature and Absolute Velocity in Turbulent Rayleigh-Bénard Convection
zhlédnutí 419Před 12 lety
Temperature and Absolute Velocity in Turbulent Rayleigh-Bénard Convection
Temperature and Vertical Velocity in Turbulent Rayleigh-Bénard Convection
zhlédnutí 414Před 12 lety
Temperature and Vertical Velocity in Turbulent Rayleigh-Bénard Convection
Rayleigh-Benard-convection at high aspect ratio
zhlédnutí 6KPřed 13 lety
Rayleigh-Benard-convection at high aspect ratio
Rayleigh-Benard-convection in two dimensions
zhlédnutí 31KPřed 14 lety
Rayleigh-Benard-convection in two dimensions
Two views of Rayleigh-Benard-Convection
zhlédnutí 4KPřed 14 lety
Two views of Rayleigh-Benard-Convection
Do you think you could share the code for the simulation of the rayleigh benard convection? Its beautiful!
Hi! This looks amazing! Would you mind sharing the code? It would be great for illustrative purposes!
Add some continent shapes and you might get the ocean currents of another planet.
Fantastic stuff. I'm interested in learning more about how this might apply to large bodies of molten rock - e.g. the lunar magma ocean, at Ra values in excessof 10^20.
This si not Rayleigh Benard instability, it is Rayleigh-Taylor instability.
which software or coder did you use for this simulation ?
Very nice! What method / numerical solver do you use to simulate the fluid? And what advection scheme (or upwind scheme) do you use to update the phase fractions (red, blue and white phases)? If you use simple bilinear interpolation (i.e. a first-order upwind scheme) to update these fields, they tend to get smeared out over time, but it looks like the separation between the difference phases are kept very well in this simulation (although maybe that is just because the grid you use to simulate this on is four times as fine as the video resolution).
vbvb
The link to the arxiv preprint is broken. May I have the link to the article?
Thanks for the hint! We fixed the link.
So cool! Would you mind sharing Ra, Pr, etc?
ok
Is this what happens you put milk in your coffee and stir? 😊
seasons on Jupiter be like
Very sexy!
i love it!
Amazing
Thank you very much for sharing this beautiful result. Could you please provide a precise reference to this work?
Thank you very much for sharing this beautiful result. Could you please provide a precise reference to this work?
what Rayleigh number?
Yes
Hi I'm doing similar kind of simulation using firefoam and stuck badly in capturing a mistake and getting wrong temp. Profile. Need some urgent help... Can you please help? my email is - janeshwar09@gmail.com
Why eulerian coordinates visualize the viscosity influence however, euler equation is neglect the viscous role.
Eulerian coordinates have nothing to do with the Euler equations.
How long did that take to compute???
Looks strangely similar to simulations of stars forming from clouds of gas. Stellar!
Yes
Hii sir/ where are you from .
It's interesting that this develops into more or less a single overturning cell, with most of the ascent in one portion of the domain and most of the descent roughly halfway across the domain. Is that a robust result at these parameter settings? Over what parameter ranges would an organized overturning cell like that be expected to emerge, as opposed to disorganized, "popcorn" convection? Thanks! Awesome video.
Could you explain what (if anything) is evolving over time? A change in parameters or just letting the simulation run its course with the same constant values?
Amazing! What is your visualization tool?
Beautiful man
Thank you for the video! Is there any reason why the lattice is formed by posivite (yellow) vortices and not the negative ones?
This is called a spontaneous symmetry breaking. If you repeat the simulation many times with different initial conditions, you will find positive vortices in one half of the cases and negative vortices in the other half.
Looks great. Is it a 2d world or a slice of a 3D world?
10hour loop would be nice
Credits of this simulation must be given for which person?
Hi. Beautiful simulation! Are there an research article on the topic?
Just when I thought the picture was impressive, I read the description! 🤯🤯🤯 If you could get this to play in a ten hour loop, with a fluid transition between cuts?! Oh👏🏼My👏🏼Goodness !!!!! 😍 ♥️🖤, A Dorothy In Kansas A Freak In Red Mary Janes
Wow this would be great for simulating the clouds and convections of a gas giant.
very nice :) may I ask, you didn't limit the motion of the fluid on the left and right? and if not how far left and right did you calculate? thanks
I believe, he has periodic lateral boundary conditions (vortexes exiting the computational domain on the right enter the domain on the left).
Looks incredible! Would it be possible to re-use this video for a talk about turbulence?
Sure, just quote our youtube channel.
@@michaelwilczek8676 Brilliant - thanks!
Nature is the best artist
hi, which program in this sumulation is used ??
amazing
trippy! check also this Rayleigh number calculator: www.fxsolver.com/browse/formulas/Rayleigh+Number
Is it DNS?
Yes!
Please tell me how you made this. did you write the program yourself?
Hi, the simulation looks great. What initial condition did u use for the simulation? Just curious
"Blue = hot fluid, red = cold fluid." I think you mean the opposite.
Beautiful! but in the two-dimensional case the flow can not be considered as turbulent because in two-dimensional case there is no mechanism of the vortex stretching.
Turbulence is the process of stretching and tilting of vortex tubes in the flow. In 2D the vortex tubes are all parallel to the z-axis and tilting of the vortex tubes is therefore not possible. However the stretching is still possible, but with the absence of the tilting, you will get an inverse cascade and formation of large scale strutures.
Outstanding. I could not decide if it was an experiment or simulation before I read the description.
amazing,wihch sofware was used?