#vortices — Public Fediverse posts

Frog Kick

A toad swims across a pond in this award-winning image from photographer Paul Hobson. The shot was actually captured from below the water, with the camera kept dry in a glass housing. Although the frog appears to be mid-leap, the light-distorting ripples around its feet hint at the flow its kick generated. It’s reminiscent of the vortices left by water striders as they move. (Image credit: P. Hobson/BWPA; via Colossal)

Explaining the Swirl of Wildfire Smoke

In recent years, smoke from powerful wildfires has raised questions among atmospheric scientists by always swirling in the same direction. The confounding structures were observed in the stratosphere, where smoke injected at around 15 kilometers in altitude absorbed sunlight and rose further, up to about 35 kilometers of altitude. The rising column of fluid would stretch, causing any residual rotation to get stronger and form vortices.

None of this was a surprise. What was surprising is that all of the observed vortices were anticyclones, when theory–at least for a heat-driven vortex from a stationary heating source–called for a cyclone-anticyclone pair.

Researchers looked at how a self-heating (and, therefore, moving) source would rotate. They concluded that this, too, would create a pair of vortices–one cyclonic and one anticyclonic–but the anticyclone would be stronger than the cyclone that trailed behind it. By further considering the vertical shear the vortex pair would encounter, the researchers found that the trailing cyclone could get stripped away, leaving behind only the anticyclone–matching our wildfire observations. (Image credit: J. Stevens/NASA Earth Observatory; research credit: K. Shah and P. Haynes 1, 2; via APS)

Scientists Observe Mysterious Light Wave Vortices Moving Faster Than Light

Dark spots within lightwaves may appear to break the speed of light, according to new research from Technion-Israel…
#NewsBeep #News #Physics #Einstein'sgeneralrelativity #fasterthanlight #LightSpeed #lightwaves #Science #UK #UnitedKingdom #vortices
https://www.newsbeep.com/uk/502793/

https://www.europesays.com/uk/859348/ Scientists Observe Mysterious Light Wave Vortices Moving Faster Than Light #Einstein'sGeneralRelativity #FasterThanLight #LightSpeed #LightWaves #Physics #Science #UK #UnitedKingdom #vortices

Scientists Observe Mysterious Light Wave Vortices Moving Faster Than Light

Dark spots within lightwaves may appear to break the speed of light, according to new research from Technion-Israel…
#NewsBeep #News #Science #CA #Canada #Einstein'sgeneralrelativity #fasterthanlight #lightspeed #lightwaves #vortices
https://www.newsbeep.com/ca/568275/

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

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

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

¡#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 🌀

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

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

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

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

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