Flamingo Fluid Dynamics, Part 2: The Game’s a Foot

Yesterday we saw how hunting flamingos use their heads and beaks to draw out and trap various prey. Today we take another look at the same study, which shows that flamingos use their footwork, too. If you watch flamingos on a beach, in muddy waters, or in a shallow pool, you’ll see them shifting back and forth as they lift and lower their feet. In humans, we might attribute this to nervous energy, but it turns out it’s another flamingo hunting habit.

As a flamingo raises its foot, it draws its toes together; when it stomps down, its foot spreads outward. This morphing shape, researchers discovered, creates a standing vortex just ahead of its feet — right where it lowers its head to sample whatever hapless creatures it has caught in this swirling vortex. And the vortex, as shown below, is strong enough to trap even active swimmers, making the flamingo a hard hunter to escape. (Image credit: top – L. Yukai, others – V. Ortega-Jimenez et al.; research credit: V. Ortega-Jimenez et al.; submitted by Soh KY)

#biology #flamingo #flowVisualization #fluidDynamics #fluidsAsArt #physics #science #vortices

Flamingo Fluid Dynamics, Part 1: A Head in the Game

Flamingos are unequivocally odd-looking birds with their long skinny legs, sinuous necks, and bent L-shaped beaks. They are filter-feeders, but a new study shows that they are far from passive wanderers looking for easy prey in shallow waters. Instead, flamingos are active hunters, using fluid dynamics to draw out and trap the quick-moving invertebrates they feed on. In today’s post, I’ll focus on how flamingos use their heads and beaks; next time, we’ll take a look at what they do with their feet.

Feeding flamingos often bob their heads out of the water. This, it turns out, is not indecision, but a strategy. Lifting its flat upper forebeak from near the bottom of a pool creates suction. That suction creates a tornado-like vortex that helps draw food particles and prey from the muddy sediment.

When feeding, flamingos will also open and close their mandibles about 12 times a second in a behavior known as chattering. This movement, as seen in the video above, creates a flow that draws particles — and even active swimmers! — toward its beak at about seven centimeters a second.

Staying near the surface won’t keep prey safe from flamingos, either. In slow-flowing water, the birds will set the upper surface of their forebeak on the water, tip pointed downstream. This seems counterintuitive, until you see flow visualization around the bird’s head, as above. Von Karman vortices stream off the flamingo’s head, which creates a slow-moving recirculation zone right by the tip of the bird’s beak. Brine shrimp eggs get caught in these zones, delivering themselves right to the flamingo’s mouth.

Clearly, the flamingo is a pretty sophisticated hunter! It’s actively drawing out and trapping prey with clever fluid dynamics. Tomorrow we’ll take a look at some of its other tricks. (Image credit: top – G. Cessati, others – V. Ortega-Jimenez et al.; research credit: V. Ortega-Jimenez et al.; submitted by Soh KY)

#biology #filterFeeding #flamingo #flowVisualization #fluidDynamics #physics #science #suction #vortices

Filtering Like a Manta Ray

As manta rays swim, they’re constantly doing two important — but not necessarily compatible — things: getting oxygen to breathe and collecting plankton to eat. That requires some expert filtering to send food particles toward their stomach and oxygen-rich water to their gills. Manta rays do this with a built-in filter that resembles an industrial crossflow filter. Researchers built a filter inspired by a manta ray’s geometry, and found that it has three different flow states, based on the flow speed. At low speeds, flow moves freely down the filter’s channels; in a manta, this would carry both water and particles toward the gills. At medium speeds, vortices start to form at the entrance to the filter channels. This sends large particles downstream (toward a manta’s digestive system) while water passes down the channels. At even greater speeds, each channel entrance develops a vortex. That allows water to pass down the filter channels but keeps particles out. (Image credit: manta – N. Weldingh, filter – X. Mao et al.; research credit: X. Mao et al.; via Ars Technica)

#biology #filterFeeding #filtration #flowVisualization #fluidDynamics #mantaRay #physics #science #vortices

Kolk (vortex) (Oceanography 🌊)

A kolk is an underwater vortex causing hydrodynamic scour by rapidly rushing water past an underwater obstacle. High-velocity gradients produce a high-shear rotating column of water, similar to a tornado. Kolks can pluck multiple-ton blocks of rock and transport them in suspension for kilometres. Kolks leave clear evidence in the form of kolk lakes, a kind...

https://en.wikipedia.org/wiki/Kolk_(vortex)

#Kolk #Vortices #Oceanography #Geomorphology #Hydrodynamics

Here's another video of the dry ice 'smoke' doing its thing. #slowMotion #physics #vortices #slomo #fluidDynamics #🧪

Crowd Vortices

The Feast of San Fermín in Pamplona, Spain draws crowds of thousands. Scientists recently published an analysis of the crowd motion in these dense gatherings. The team filmed the crowds at the festival from balconies overlooking the plaza in 2019, 2022, 2023, and 2024. Analyzing the footage, they discovered that at crowd densities above 4 people per square meter, the crowd begins to move in almost imperceptible eddies. In the animation below, lines trace out the path followed by single individuals in the crowd, showing the underlying “vortex.” At the plaza’s highest density — 9 people per square meter — one rotation of the vortex took about 18 seconds.

The team found similar patterns in footage of the crowd at the 2010 Love Parade disaster, in which 21 people died. These patterns aren’t themselves an indicator of an unsafe crowd — none of the studied Pamplona crowds had a problem — but understanding the underlying dynamics should help planners recognize and prevent dangerous crowd behaviors before the start of a stampede. (Image credit: still – San Fermín, animation – Bartolo Lab; research credit: F. Gu et al.; via Nature)

#activeMatter #collectiveMotion #crowds #fluidDynamics #physics #science #vortices

Tropical cyclone (Storm 🌪️)

A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its location and strength, a tropical cyclone is called a hurricane, typhoon, tropical storm, cyclonic st...

https://en.wikipedia.org/wiki/Tropical_cyclone

#TropicalCyclone #Storm #Vortices #TypesOfCyclone #WeatherHazards #TropicalCyclones

Tropical cyclone (Storm 🌪️)

A tropical cyclone is a rapidly rotating storm system with a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its location and strength, a tropical cyclone is called a hurricane, typhoon, tropical storm, cyclonic ...

https://en.wikipedia.org/wiki/Tropical_cyclone

#TropicalCyclone #Storm #Vortices #TypesOfCyclone #WeatherHazards #TropicalCyclones

#vortices and capillary waves can be seen easily thanks to light refraction on the bottom of this quiet #glacial stream in the #pyrenees.
#fluiddynamics #physics #science

Tropical cyclone (Storm 🌪️)

A tropical cyclone is a rapidly rotating storm system with a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its location and strength, a tropical cyclone is called a hurricane, typhoon, tropical storm, cyclonic ...

https://en.wikipedia.org/wiki/Tropical_cyclone

#TropicalCyclone #Storm #Vortices #TypesOfCyclone #WeatherHazards #TropicalCyclones

A new technique reveals high-speed trajectories of oscillating #vortices and shows that they are 10,000 times lighter than expected. #superconductor #physics https://physics.aps.org/articles/v17/117?utm_campaign=weekly&utm_medium=email&utm_source=emailalert

Massive black holes drag and warp the spacetime around them in extreme ways. Observing these effects firsthand is practically impossible, so physicists look for laboratory-sized analogs that behave similarly. Fluids offer one such avenue, since fluid dynamics mimics gravity if the fluid viscosity is low enough. To chase that near-zero viscosity, experimentalists turned to superfluid helium, a version of liquid helium near absolute zero that flows with virtually no viscosity. At these temperatures, vorticity in the helium shows up as quantized vortices. Normally, these tiny individual vortices repel one another, but a spinning propeller — much like the blades of a blender — draws tens of thousands of these vortices together into a giant quantum vortex.

With that much concentrated vorticity, the team saw interactions between waves and the vortex surface that directly mirrored those seen in black holes. In particular, they detail bound states and black-hole-like ringdown phenomena. Now that the apparatus is up and running, they hope to delve deeper into the mechanics of their faux-black holes. (Image credit: L. Solidoro; research credit: P. Švančara et al.; via Physics World)

https://fyfluiddynamics.com/2024/05/black-holes-in-a-blender/

#astrophysics #blackHole #fluidDynamics #physics #quantumVortex #science #superfluid #superfluidHelium #vortices #vorticity

Some 20,000 years ago, a massive star blew off a ring of dust and gas that expanded into the surrounding interstellar medium. Later, in 1987, the star exploded as supernova 1987A. That explosion lit the surrounding area, revealing a clumpy ring astronomers have struggled to explain. But a new team believes they have a fluid dynamical answer: the Crow instability.

Closer to home, we see the Crow instability when an airplane’s contrails break up. It happens when two vortices that rotate in opposite directions are close to one another. Any wobble in one vortex is enhanced by the influence of its neighbor. Eventually, this breaks the original vortices apart and causes them to reform as a series of smaller vortex rings.

In the case of supernova 1987A, the researchers propose that the star originally blew off two vortex rings that, due to their mutual influence, broke down into a clumpy ring of vortices. (Image credits: NASA/ESA/CSA/M. Matsuura/R. Arendt/C. Fransson and NASA/ESA/A. Angelich + M. Wadas et al.; research credit: M. Wadas et al.; via APS Physics)

https://fyfluiddynamics.com/2024/05/supernova-rings/

#astrophysics #CrowInstability #fluidDynamics #instability #physics #science #supernova #vortexRings #vortices

Vortex loop dynamics and dynamical quantum phase transitions in three-dimensional fermion matter

During nonequilibrium dynamics vortices can form in the phase of the Green's function in three-dimensional fermionic quantum matter. In this work we show that these vortices form topological structures in the form of loops in momentum space, which are created and annihilated in the vicinity of dynamical quantum phase transitions:

https://doi.org/10.1103/PhysRevB.109.L140303

#quantum #vortices

#Dawn begins to break in some far-flung #fractal universe.

Created in #Tierazon. #Blue #Vortices #Fractals #FractalArt #FractalArchive.

@drvgraber

This is the best word picture of the formation of #supernovas and #neutronstars

I especially like the concept of using "cold atom experiments as analog #quantum #computers" to study the #vortices which occur in ultra-cold #gases below the Fermi temperature.

Sounds a little like trying to model the earth's atmosphere when thermodynamic properties are goosed by #climatechange

#astronomy #astrophysics #thermodynamics

¡#HolaCiencia! Una calle de #vórtices de Von #Kármán es un patrón de remolinos causados por la separación no estacionaria de un fluido tras un obstáculo • vía Rainmaker1973/TW Jousefm2/TW #VideoCiencia Sarwesh Narayan Parbat/YT 🌀

Referenced link: https://phys.org/news/2022-12-peculiar-links-viking-quantum-vortices.html
Discuss on https://discu.eu/q/https://phys.org/news/2022-12-peculiar-links-viking-quantum-vortices.html

Originally posted by Phys.org / @physorg_com@twitter.com: https://twitter.com/physorg_com/status/1602301007697936384#m

A peculiar protected structure links Viking knots with quantum #vortices @CommsPhys https://www.nature.com/articles/s42005-022-01071-2 https://phys.org/news/2022-12-peculiar-links-viking-quantum-vortices.html

Scientists at the U.S. Department of Energy’s (#DOE) Argonne National Laboratory want to replace the bar #magnets with tiny magnetic #vortices. As tiny as billionths of a meter, these vortices are called #skyrmions, which form in certain magnetic materials.
#QuantumScience #AI #ArtificialIntelligence #Physics #sflorg
https://www.sflorg.com/2022/11/qs11212202.html

A showcase of Saturn's active atmosphere! View of the #dynamics of #Saturn #atmosphere at the visible #cloud layer, from our global #climate computer #model, highlighting #JetStream (red<>blue steps) #vortices (rounded red or blue areas) #waves (oscillations from red to blue) #eddies (random red and blue fluctuations). This is a #PotentialVorticity map and this comes from our paper, see free #arxiv #PDF version https://arxiv.org/pdf/1811.01250.pdf #astro #climate #FluidDynamics #gfd #astrodon #SolarSytem