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1000 results for “fluiddyn”
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A Drop of Algae
Spheres of a Volvox colonial algae glow green inside a droplet in this award-winning microphotograph by Jan Rosenboom. Pinned on an inclined surface, the droplet is frozen in a balance between gravity and surface tension that keeps its shape–and its contact angles–asymmetric. Droplets will also take on a shape similar to this when air is blowing past them. (Image credit: J. Rosenboom; via Ars Technica)
#biology #contactLine #droplets #fluidDynamics #fluidsAsArt #science #sessileDrop -
“Rivers and Dunes”
Taken from a Cessna aircraft, photographer J. Fritz Rumpf’s image of a Brazilian landscape appears abstract. But it captures a serpentine river and surrounding dunes, dyed brown by decaying plant matter and sculpted by the forces of wind and current. This shot is part of a portfolio that won him the title of 2025 International Landscape Photographer of the Year. (Image credit: J. Rumpf; via ILPOTY)
#dunes #erosion #fluidDynamics #fluidsAsArt #physics #science -
“Moment of Creation”
Bubbles caught in ice resemble the growth of a cellular organism in this photograph of Tatiewa Lake in Japan, taken by Soichiro Moriyama. When water freezes, gases dissolved in it come out of solution, but depending on the speed and direction of freezing, these bubbles do not always escape before ice forms around them, freezing pockets of gas within the ice’s structure. (Image credit: S. Moriyama; via ILPOTY)
#bubbles #dissolution #fluidDynamics #fluidsAsArt #freezing #ice #physics #science -
“Legends of the Falls”
Strong winds blew curtains of mist across Skógafoss in this image of nesting northern fulmars by photographer Stefan Gerrits. Despite water’s high density compared to air, fine droplets are able to stay aloft for long periods, given the right breeze. Mists, fogs, and sea spray can float surprising distances; droplets exhaled from our lungs can persist even farther. (Image credit: S. Gerrits; via Colossal)
#droplets #fluidDynamics #fluidsAsArt #physics #science -
“Melting Snowflake”
It’s hard to preserve something as ephemeral as a snowflake, as seen in this microphotograph by Michael Robert Peres. Despite the old adage, it is possible to make identical snowflakes, but it requires mirroring the freezing conditions exactly, including both temperature and humidity. Here, the snowflake’s crystalline structure survives as a ghost in a melting droplet. (Image credit: M. Peres; via Ars Technica)
#fluidDynamics #fluidsAsArt #freezing #melting #physics #science #snowflakes
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“Magnetic Vortex”
The Macro room team is back with a video featuring their signature colorful cleverness. This time they’re using a magnetic stirrer to swirl up some mesmerizing flows. It’s well worth a watch. (Video and image credit: Macro Room)
#flowVisualization #fluidDynamics #fluidsAsArt #physics #science #vortex
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“500,000-km Solar Prominence Eruption”
It’s difficult at times to fathom the scale and power of fluid dynamics beyond our day-to-day lives. Here, twists of the Sun‘s magnetic field propel a jet of plasma more than 500,000 kilometers out from its surface in an enormous solar prominence eruption. To give you a sense of scale for this random solar burp, that’s bigger than ten times the distance to satellites in geostationary orbit. (Image credit: P. Chou; via Colossal)
#astrophysics #fluidDynamics #fluidsAsArt #magnetohydrodynamics #physics #science #sun
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The Balvenie
Photographer Ernie Button explores the stains left behind when various liquors evaporate. This one comes from a single malt scotch whisky by The Balvenie. The stain itself is made up of particles left behind when the alcohol and water in the whisky evaporate. The pattern itself depends on a careful interplay between surface tension, evaporation, pinning forces, and internal convection as the whisky puddle dries out. (Image credit: E. Button/CUPOTY; via Colossal)
#alcohol #deposition #evaporation #fluidDynamics #fluidsAsArt #physics #science #surfaceTension
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Spores Get a Lift
Mushrooms have the challenging task of dispersing spores, typically from heights no more than a few centimeters above the ground. At that altitude, viscosity and friction with the ground mean that air barely moves, if it does at all. And mushrooms rely on a wide range of methods, from explosive launches to rain assistance to making their own weather. Every one of these methods gives spores a lift in altitude to reach higher winds and greater dispersal. (Image credit: A. Bejczi/CUPOTY; via Colossal)
#biology #dispersion #fluidDynamics #fluidsAsArt #mushrooms #physics #science
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A Rough Day
Winds from the north made for wild conditions at Nazaré in Portugal. Photographer Ben Thouard caught these crashing waves in the late afternoon, when the low sun angle illuminated the spray of the surf. Every year teratons of salt and biomass move from the ocean to the atmosphere, much of it through turbulent wave action driven by the wind. Here, the wind rips droplets off of wave crests, but smaller droplets reach the atmosphere when bubbles–trapped underwater by crashing waves–reach the surface and burst. (Image credit: B. Thouard/OPOTY; via Colossal)
#fluidDynamics #fluidsAsArt #ocean #oceanWaves #physics #science #turbulence
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A Gentoo Flotilla
If you’re used to seeing penguins on land, their speed and grace in the water can surprise. Penguins are even capable of extra bursts of speed through supercavitation. They trap air beneath their feathers and then release it underwater when they need to move faster. Their coating of bubbles reduces their drag and gives them the extra speed to help escape predators like leopard seals. (Image credit: R. Barats/OPOTY; via Colossal)
#flowVisualization #fluidDynamics #fluidsAsArt #penguins #physics #science #supercavitation
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Frosted
Frost forms hexagonal columns on a wooden rail in this microphotograph by Gregory B. Murray. Like in snowflakes, when water molecules freeze they position themselves to form six-sided crystals. From this perspective, it looks like a miniature version of the Giant’s Causeway. (Image credit: G. Murray; via Ars Technica)
#fluidDynamics #fluidsAsArt #freezing #frost #physics #science
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Our Best Look Yet at a Solar Flare
Scientists have unveiled the sharpest images ever captured of a solar flare. Taken by the Inouye Solar Telescope, the image includes coronal loop strands as small as 48 kilometers wide and 21 kilometers thick–the smallest ones ever imaged. The width of the overall image is about 4 Earth diameters. The captured flare belongs to the most powerful class of flares, the X class. Catching such a strong flare under the perfect observation conditions is a wonderful stroke of luck.
Although astronomers had theorized that coronal loops included this fine-scale structure, the Inouye Solar Telescope is the first instrument with the resolution to directly observe structures of this size. Confirming their existence is a big step forward for those working to understand the details of our Sun. (Video and image credit: NSF/NSO/AURA; research credit: C. Tamburri et al.; via Gizmodo)
https://www.youtube.com/watch?v=WnoAq4rpLg4
#fluidDynamics #fluidsAsArt #magnetohydrodynamics #physics #science #sun
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I also want to explore more #GeometricAlgebra applied to #physics and #ComputationalPhysics (not necessarily for #FluidDynamics and #CFD, but that would be preferable as it's obviously our primary topic of relevance). I can't seem to find anything that combines #SPH and GA, so it might even lead to some new interesting venues to explore.
3/n
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Oceans Could “Burp” Out Absorbed Heat
Earth’s atmosphere and oceans form a complicated and interconnected system. Water, carbon, nutrients, and heat move back and forth between them. As humanity pumps more carbon and heat into the atmosphere, the oceans–and particularly the Southern Ocean–have been absorbing both. A new study looks ahead at what the long-term consequences of that could be.
The team modeled a scenario where, after decades of carbon emissions, the world instead sees a net decrease in carbon–which could be achieved by combining green energy production with carbon uptake technologies. They found that, after centuries of carbon reduction and gradual cooling, the Southern Ocean could release some of its pent-up heat in a “burp” that would raise global temperatures by tenths of a degree for decades to a century. The burp would not raise carbon levels, though.
The research suggests that we should continue working to understand the complex balance between the atmosphere and oceans–and how our changes will affect that balance not only now but in the future. (Image credit: J. Owens; research credit: I. Frenger et al.; via Eos)
#CFD #climateChange #computationalFluidDynamics #fluidDynamics #geophysics #heatTransfer #numericalSimulation #ocean #physics #science
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Bow Shock Instability
There are few flows more violent than planetary re-entry. Crossing a shock wave is always violent; it forces a sudden jump in density, temperature, and pressure. But at re-entry speeds this shock wave is so strong the density can jump by a factor of 13 or more, and the temperature increase is high enough that it literally rips air molecules apart into plasma.
Here, researchers show a numerical simulation of flow around a space capsule moving at Mach 28. The transition through the capsule’s bow shock is so violent that within a few milliseconds, all of the flow behind the shock wave is turbulent. Because turbulence is so good at mixing, this carries hot plasma closer to the capsule’s surface, causing the high temperatures visible in reds and yellows in the image. Also shown — in shades of gray — is the vorticity magnitude of flow around the capsule. (Image credit: A. Álvarez and A. Lozano-Duran)
#2024gofm #CFD #computationalFluidDynamics #flowVisualization #fluidDynamics #hypersonic #instability #numericalSimulation #physics #science #shockWave #turbulence
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How CO2 Gets Into the Ocean
Our oceans absorb large amounts of atmospheric carbon dioxide. Liquid water is quite good at dissolving carbon dioxide gas, which is why we have seltzer, beer, sodas, and other carbonated drinks. The larger the surface area between the atmosphere and the ocean, the more quickly carbon dioxide gets dissolved. So breaking waves — which trap lots of bubbles — are a major factor in this carbon exchange.
This video shows off numerical simulations exploring how breaking waves and bubbly turbulence affect carbon getting into the ocean. The visualizations are gorgeous, and you can follow the problem from the large-scale (breaking waves) all the way down to the smallest scales (bubbles coalescing). (Video and image credit: S. Pirozzoli et al.)
#2024gfm #breakingWave #bubbles #carbonCycle #carbonDioxide #CFD #climateChange #computationalFluidDynamics #dissolution #flowVisualization #fluidDynamics #numericalSimulation #physics #science #turbulence
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You’ll shoot your eye out: Popped champagne cork ejects CO2 at supersonic speeds - Enlarge (credit: Andy Roberts/Getty Images)
The pop of a champ... - https://arstechnica.com/?p=1859317 #computationalfluiddynamics #champagnescience #fluiddynamics #supersonic #science #physics
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Scalloped iceberg sculptures occur due to the weirdness of water - Enlarge (credit: Scott Weady)
You would think that understandi... - https://arstechnica.com/?p=1830465 #computationalfluiddynamics #fluiddynamics #science #water #ice
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Scientists model dynamic feedback loop that fuels the spread of wildfires - Enlarge / Flames spread up a hillside near firefighters at the Blue Cut Fire on August 18, 2016 nea... more: https://arstechnica.com/?p=1601493 #computationalfluiddynamics #12daysofchristmas #fluiddynamics #chemistry #wildfires #science #physics
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An interesting look at the history of research into turbulence, one of the big unsolved problems of classical physics.
#History #Physics #Turbulence #FluidDynamics #ComputationalFluidDynamics #Simulation #Mathematics
https://arstechnica.com/science/2018/10/turbulence-the-oldest-unsolved-problem-in-physics/
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“Soap Bubble Bonanza
This video offers an artistic look at a soap bubble bursting. The process is captured with high-speed video combined with schlieren photography, a technique that makes visible subtle density variations in the air. The bubbles all pop spontaneously, once enough of their cap drains or evaporates away for a hole to form. That hole retracts quickly; the acceleration of the liquid around the bubble’s spherical shape makes the retracting film break into droplets, seen as falling streaks near the bottom of the bubble. The retraction also affects air inside the bubble, making the air that touched the film curl up on itself, creating turbulence. Then, as the film completes its retraction, it pushes a plume of the once-interior air upward, as if the interior of the bubble is turning itself inside out. (Video and image credit: D. van Gils)
#flowVisualization #fluidDynamics #fluidsAsArt #physics #schlierenPhotography #science #soapBubbles
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- Gravity effects on liquid-solid contact -
Gravity affects the shape and motion of droplets. Discover its role in the Leidenfrost phenomenon in these ESPCI Paris - PSL MOOC videos.
🎥 1️⃣ https://www.youtube.com/watch?v=AqxZAKuFFAM&list=PLcbz7zf4dTyk9BqlBPLpgI48i9TiorpEi&index=8
🎥 2️⃣ https://www.youtube.com/watch?v=-y9yaGzN7J8&list=PLcbz7zf4dTyk9BqlBPLpgI48i9TiorpEi&index=9
⏳ No time right now? Save this post and come back later
#GravityEffects #FluidPhysics #Leidenfrost #FluidDynamics #Physics
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The Hydrostatic Paradox
Engineering classes often discuss hydrostatics–the physics of non-moving water–before they cover fluid dynamics and its flows. But hydrostatics is plenty challenging on its own, as Steve Mould demonstrates in this video looking at how hydrostatic pressure depends on depth (and, not, as our intuition might suggest, on shape). As always, he has some nice countertop-scale demos to go with it. (Video and image credit: S. Mould)
#DIYFluids #fluidDynamics #hydrostaticPressure #hydrostatics #physics #science -
Liquefaction in Earthquakes
In an earthquake, sand and soil particles get jostled together, forcing any water between them up toward the surface. The result is liquefaction, a state where once-solid ground starts to behave much like a liquid. Buildings can tip over and pipelines get pushed toward the surface. In this video, a geologist shows off some great demonstrations of the effect, including ones that can be easily done in a classroom with younger kids. (Video credit: California Geological Survey)
#DIYFluids #earthquake #fluidDynamics #geology #geophysics #physics #science #soilLiquefaction
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What Limits a Siphon
Siphons are a bit mind-boggling for anyone who has internalized the idea that water always flows downhill. But gravity actually allows a siphon’s water to flow up and over an obstacle, provided certain conditions are met. Steve Mould digs into the details of those conditions in this video, where he searches for the maximum height a siphon can reach.
A quick note on terminology: Steve explains that the siphon breaks when water near the top starts “boiling.” Other sources may use the term “cavitating” for this sudden phase change. There’s not–to my knowledge–a generally-agreed-upon definition that clearly distinguishes between boiling and cavitation in this situation. Whichever term you use, the water in the siphon doesn’t care; either way, it’s experiencing a local pressure that’s so low that it switches from a liquid state (where it can resist tensile forces) to a gaseous one (where it cannot resist tension). (Video and image credit: S. Mould)
#cavitation #DIYFluids #fluidDynamics #physics #science #siphon
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Spinning Water
If you spin a tank of water at a constant speed, it takes on a curved, parabolic shape–a demonstration often called Newton’s bucket. Here, a team from UCLA shows how it’s done, both in terms of the equipment needed and a concise explanation of the physics. In the rotating experiment, water is subjected to both gravity (which acts in a constant magnitude across the tank) and centrifugal force (which is stronger further from the axis of rotation). The shape that balances these forces is a paraboloid, which is why the water takes on that shape. (Video and image credit: UCLA SpinLab)
#centrifugalForce #DIYFluids #fluidDynamics #physics #rotatingFlow #science
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Active Cheerios Self-Propel
The interface where air and water meet is a special world of surface-tension-mediated interactions. Cereal lovers are well-aware of the Cheerios effect, where lightweight O’s tend to attract one another, courtesy of their matching menisci. And those who have played with soap boats know that a gradient in surface tension causes flow. Today’s pre-print study combines these two effects to create self-propelling particle assemblies.
The team 3D-printed particles that are a couple centimeters across and resemble a cone stuck atop a hockey puck. The lower disk area is hollow, trapping air to make the particle buoyant. The cone serves as a fuel tank, which the researchers filled with ethanol (and, in some cases, some fluorescent dye to visualize the flow). Like soap, ethanol’s lower surface tension disrupts the water’s interface and triggers a flow that pulls the particle toward areas with higher surface tension. But, unlike soap, ethanol evaporates, effectively restoring the interface’s higher surface tension over time.
With multiple self-propelling particles on the interface, the researchers observed a rich series of interactions. Without their fuel, the Cheerios effect attracted particles to each other. But with ethanol slowly leaking out their sides, the particles repelled each other. As the ethanol ran out and evaporated, the particles would again attract. By tweaking the number and position of fuel outlets on a particle, the researchers found they could tune the particles’ attractions and motility. In addition to helping robots move and organize, their findings also make for a fun educational project. There’s a lot of room for students to play with different 3D-printed designs and fuel concentrations to make their own self-propelled particles. (Research and image credit: J. Wilt et al.; via Ars Technica)
#3DPrinting #CheeriosEffect #DIYFluids #evaporation #flowVisualization #fluidDynamics #marangoniEffect #physics #science #surfaceTension
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Crown Splash
When a falling drop hits a thin layer of water, the impact sends up a thin, crown-shaped splash. This research poster shows a numerical simulation of such a splash in the throes of various instabilities. The crown’s thick edges are undergoing a Rayleigh-Plateau instability, breaking into droplets much the way a dripping faucet does. On the far side, the crown has rapidly expanding holes that pull back and collide. The still-intact liquid sheet at the base of the crown shows some waviness, as well, hinting at a growing instability there. (Image credit: L. Kahouadji et al.)
#2024gofm #CFD #computationFluidDynamics #crownSplash #fluidDynamics #instability #physics #PlateauRayleighInstability #science #splashing
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Crown Splash
When a falling drop hits a thin layer of water, the impact sends up a thin, crown-shaped splash. This research poster shows a numerical simulation of such a splash in the throes of various instabilities. The crown’s thick edges are undergoing a Rayleigh-Plateau instability, breaking into droplets much the way a dripping faucet does. On the far side, the crown has rapidly expanding holes that pull back and collide. The still-intact liquid sheet at the base of the crown shows some waviness, as well, hinting at a growing instability there. (Image credit: L. Kahouadji et al.)
#2024gofm #CFD #computationFluidDynamics #crownSplash #fluidDynamics #instability #physics #PlateauRayleighInstability #science #splashing