Simulating a Sneeze

Sneezing and coughing can spread pathogens both through large droplets and through tiny, airborne aerosols. Understanding how the nasal cavity shapes the aerosol cloud a sneeze produces is critical to understanding and predicting how viruses could spread. Toward that end, researchers built a “sneeze simulator” based on the upper respiratory system’s geometry. With their simulator, the team mimicked violent exhalations both with the nostrils open and closed — to see how that changed the shape of the aerosol cloud produced.

The researchers found that closed nostrils produced a cloud that moved away along a 18 degree downward tilt, whereas an open-nostril cloud followed a 30-degree downward slope. That means having the nostrils open reduces the horizontal spread of a cloud while increasing its vertical spread. Depending on the background flow that will affect which parts of a cloud get spread to people nearby. (Image and research credit: N. Catalán et al.; via Physics World)

“ #Trump’s recognition of the #turbulence in the U.S. #economy was a #reversal from previous cheering that his policies would deliver quick victories to #voters and #businesses, and it stood in contrast to reassurances from his own advisers Sunday that no #recession was in sight. … ” (15/n)
https://stocks.apple.com/AZm_px_s7QEW_6yypFDNEaA

Filtering by Sea Sponge

Gathering oil after a spill is fiendishly difficult. Deploying booms to corral and soak up oil at the water surface only catches a fraction of the spill. A recent study instead turns to nature to inspire its oil filter. The team was inspired by the Venus’ flower basket, a type of deep-sea sponge with a multi-scale structure that excels at pulling nutrients out of complex flow fields. The outer surface of the sponge has helical ridges that break up the turbulence of any incoming flow, helping the sponge stay anchored by reducing the force needed to resist the flow. Beneath the ridges, the sponge’s skeleton has a smaller, checkered pattern that further breaks up the flow as it enters into the sponge’s hollow body. Within this cavity, the flow is slower and swirling, giving plenty of time for nutrients in the water to collide with the nutrient-gathering flagellum lining the sponge.

By mimicking this three-level structure, the team built a capable oil-capturing device that can filter even emulsified oil from the water. They swapped the flagellum with a (replaceable) oil-adsorbing material and found that their filter captured more than 97% of oil across a range of flow conditions. (Image credit: NOAA; research credit: Y. Yu et al.; via Physics World)

Salt Affects Particle Spreading

Microplastics are proliferating in our oceans (and everywhere else). This video takes a look at how salt and salinity gradients could affect the way plastics move. The researchers begin with a liquid bath sandwiched between a bed of magnets and electrodes. Using Lorentz forcing, they create an essentially 2D flow field that is ordered or chaotic, depending on the magnets’ configuration. Although it’s driven very differently, the flow field resembles the way the upper layer of the ocean moves and mixes.

The researchers then introduce colloids (particles that act as an analog for microplastics) and a bit of salt. Depending on the salinity gradient in the bath, the colloids can be attracted to one another or repelled. As the team shows, the resulting spread of colloids depends strongly on these salinity conditions, suggesting that microplastics, too, could see stronger dispersion or trapping depending on salinity changes. (Video and image credit: M. Alipour et al.)

Turbulence 1997 Filmini izle
#Turbulence #AksiyonFilmleri #Komedi #Film #Filmizle #Diziizle #izle #Fullizle #sinema

https://www.filmizleilk.com/turbulence-1997/

An Article in the Annual Review of Condensed Matter Physics on Turbulence by KR Sreenivasan and J Schumacher
https://www.annualreviews.org/content/journals/10.1146/annurev-conmatphys-031620-095842

What is the turbulence problem, and when can we say it’s solved? This deep dive by Sreenivasan & Schumacher explores the math, physics, and engineering challenges of turbulence—from Navier-Stokes equations to intermittency and beyond. A must-read for anyone fascinated by chaos, complexity, and the unsolved mysteries of fluid dynamics!

A summary of the talk presented by KR Sreenivasan in December 2023 at the International Center for Theoretical Sciences (ICTS-TIFR) in Bengaluru, as part of a program on field theory and turbulence.
https://www.youtube.com/watch?v=fwVSBYh-KC4

"Field Theory and Turbulence" program link: https://www.icts.res.in/discussion-meeting/ftt

#FluidDynamics #Physics #NavierStokes #UnsolvedMystery #Mechanics #Dynamics #FluidMechanics #Science #Chaos #TurbulentMotion #Randomness #Chaotic #Fluid #ClassicalMechanics
#Turbulence

https://www.europesays.com/1905712/ Landry supports Trump’s tariffs but warns of ‘turbulence’ for Louisiana’s economy #2025LegislativeSession #BusinessImpact #ChamberPACLuncheon #EconomicPolicy #Economy #EnergyIndustry #FairTrade #FreeTrade #FullEffect #good #Gov.JeffLandry #Gov.Landry #industry #InternationalTrade #JobMarket #landry #Louisiana #LouisianaBusiness #LouisianaEconomy #LouisianaIndustries #MetalTariffs #ports #ReciprocalTariffs #state #tariff #thing #TradePolicy #trump #TrumpTariffs #turbulence

Icelandic Flows

Known as “The Land of Fire and Ice,” Iceland has some of the most striking landscapes around. Photographer Jennifer Esseiva captures auroras, waterfalls, geysers, rivers, and more in this series from her 2024 trip to the island. Every one of these images bears the fingerprints of fluid dynamics: plasma flows lighting up the night sky; rivers of lava that formed the land; rivers and oceans that carve through the landscape; and pressurized, superheated water that shoots up from underground plumbing. (Image credit: J. Esseiva; via Colossal)

Flooding the Mediterranean

Nearly 6 million years ago, the Mediterranean was cut off from the ocean and evaporated faster than rivers could replenish it. This created a salty desert that persisted until about 5.3 million years ago. One hypothesis — the Zanclean megaflood — suggests that the Mediterranean refilled rapidly through an erosion channel near the Strait of Gilbraltar. A new study bolsters the concept by identifying geological features near Sicily consistent with the megaflood.

The team point to a grouping of over 300 ridges near the Sicily Sill, once a land bridge dividing the eastern and western Mediterranean and now underwater. The ridges are layered in debris but aren’t streamlined, suggesting they were rapidly deposited by turbulent waters, and date to the period of the proposed flooding. For more on the Zanclean Flood, check out this older post. (Image credit: R. Klavins; research credit: A. Micallif et al.; via Gizmodo)

Kolmogorov Turbulence

Turbulent flows are ubiquitous, but they’re also mindbogglingly complex: ever-changing in both time and space across length scales both large and small. To try to unravel this complexity, scientists use simplified model problems. One such simplification is Kolmogorov flow: an imaginary flow where the fluid is forced back and forth sinusoidally. This large-scale forcing puts energy into the flow that cascades down to smaller length scales through the turbulent energy cascade. Here, researchers depict a numerical simulation of a turbulent Kolmogorov flow. The colors represent the flow’s vorticity field. Notice how your eye can pick out both tiny eddies and larger clusters in the flow; those patterns reflect the multi-scale nature of turbulence. (Image credit: C. Amores and M. Graham)

Visualizing Unstable Flames

Inside a combustion chamber, temperature fluctuations can cause sound waves that also disrupt the flow, in turn. This is called a thermoacoustic instability. In this video, researchers explore this process by watching how flames move down a tube. The flame fronts begin in an even curve that flattens out and then develops waves like those on a vibrating pool. Those waves grow bigger and bigger until the flame goes completely turbulent. Visually, it’s mesmerizing. Mathematically, it’s a lovely example of parametric resonance, where the flame’s instability is fed by system’s natural harmonics. (Video and image credit: J. Delfin et al.; research credit: J. Delfin et al. 1, 2)

#Scientists make ‘rare advance’ in tackling the oldest #unsolved #problem in #physics.

❛❛ understanding the #pattern & #structure of #turbulence … many practical applications in #science and #engineering, potentially improving the design of #airplanes, #cars, #propellers, artificial #hearts and making #weather prediction more accurate ❜❜

https://www.CNN.com/2025/02/06/science/turbulence-physics-oldest-unsolved-problem/index.html 2025 Feb 06
https://www.Science.org/doi/10.1126/sciadv.ads5990 2025 Jan 29

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.)

F0325TSPnow Retiree Monday Fund Debrief –-Turbulence

G+0.04%, F+0.08%, C-0.75%, S-1.05%, I-1.25%

A bumpy ride as Wall Street rolled out the magic red carpet for tariffs. Considering pre-market was showing -2% it could have been a lot worse today. The G fund is calling.

https://tspretiree.blogspot.com/2025/02/f0325tspnow-retiree-monday-fund-debrief.html

I am beginning to wonder if the financial turbulence in the UK money markets is the modern equivalent of the traitors who brought about the downfall of a "legitimate" monarch (the Glorious Revolution) to replace him with someone who was more aligned to the traitors beliefs?
Are the money markets selling out to the people, like Musk, who want the downfall of the legitimate British government and replaced it with them even more corrupt is in their control?
#Finance #FinancialMarket #Turbulence

“Magic of the North”

Fires glow above and below in this award-winning image from photographer Josh Beames. In the foreground, lava from an Icelandic eruption spurts into the air and seeps across the landscape as it slowly cools. Above, the northern aurora ripples through the night sky, marking the dance of high-energy particles streaming into our atmosphere, guided by the lines of our magnetic field. Throw in some billowing turbulent smoke, and it’s hard to get more fluid dynamical (or beautiful!) than this. (Image credit: J. Beames/NLPOTY; via Colossal)

Soaring Through the Pillars of Creation

The Pillars of Creation are an iconic feature nestled within the Eagle Nebula. For decades, the public has admired Hubble’s images of this stellar nursery, and, in this video, we get to fly between the pillars, shifting between Hubble’s visible light imagery and JWST’s infrared views. In visible light, glowing dust obscures the interior of the pillars, drawing our eyes instead to the dusty shapes eroded by the stellar winds of these young stars. In infrared wavelengths, we see further into the pillars, revealing individual stars burning at the ends of the pillars’ fingers. Being able to peer at the same problem through different techniques — here visible and infrared light — reveals more to scientists than either mode can on its own. (Image/video credit: G. Bacon et al.; via Gizmodo)

What kind of clouds are these? What kind of turbulence would I expect around them. #wx #pdxtst #weather #aviation #generalaviation #ga #flying #clouds #turbulence

New work: #ALLUVION

Over the past two months I've been actively revisiting, updating/extending and now close to finishing this 1.5 year long journey... The actual journey has been much longer, been toying with (faux) fluid sims since ~2007...

A 50 second preview of one of my fave variations, best enjoyed fullscreen... Tried to achieve some molten, dichroic/irridescent glass & oilfilm aesthetics here, but there're over a dozen of other very different routes/styles possible too, with 25+ parameters to tweak the simulation and look & feel...

Made with https://thi.ng/shader-ast & https://thi.ng/shader-ast-stdlib