In this ASMR video, black ink diffuses in water. When the video starts, the ink is so diffuse that it’s not apparent the video is playing backward. It’s only as specific structures — things like Rayleigh-Taylor instabilities, plumes, and jets — coalesce from the background that we recognize the time reversal. Though it’s probably unintentional, this makes for a neat, subtle commentary on the nature of isotropic turbulence. (Video and image credit: Wryfield Lab)
In “Starlit,” filmmaker Roman de Giuli leverages paint, ink, water, and oil to create astronomical views. Colorful droplets spin past like neon exoplanets. Shards of glitter form comets. Satellite droplets become moons about their larger sibling. (Video and image credit: R. de Giuli)
A surfer duck-dives beneath a passing wave in this image from photographer John Barton. I always love seeing big waves from this underwater perspective. The turbulent surf looks like storm clouds, and sometimes you see features that are invisible from the surface. Barton’s shot captures the dichotomy of serenity and chaos in the breaking surf. (Image credit: J. Barton/OPOTY; via Colossal)
In “Black,” filmmaker Susi Sie combines her visuals of shifting ferrofluids with the music and soundscape of Clemens Haas to create an ominous, almost claustrophobic vibe. With fast cuts and shallow focus, the sharpened points of the normal-field instability appear as flashes of brightness in the dark. At times, the liquid’s surface looks almost like a speaker cone, which is appropriate since ferrofluids are frequently used in speakers to provide cooling and enhance performance. (Video and image credit: Susi Sie)
The sun’s corona — its outer atmosphere — is usually impossible to see, since it’s far outshone by the rest of the sun. But during a total solar eclipse, the moon blocks out all but the vibrant, wispy corona. Getting a detailed image of the corona is tough; it’s constantly shifting. For this image, engineer Phil Hart used 5 main cameras, 4 refractors, 2 laptops, and plenty of digital image processing to capture some incredible details of the plasma and hot gases dancing along the sun’s magnetic field lines. You can learn about the awesome effort behind this image — and see more awesome photos from the eclipse — at his site. (Image credit: P. Hart; via APOD)
Colored inks bulge and billow around flowers in filmmaker Christopher Dormoy’s “Aquakosmos – Ch. 2”. Because ink is denser than the surrounding water, it sinks, forming mushroom-like shapes as the Rayleigh-Taylor instability takes over. One of the fun things about this particular video is that we see the Rayleigh-Taylor instability at many different sizes, depending on the size and speed of different falling dyes. (Video and image credit: C. Dormoy)
Turbulent flows feature swirling eddies over a range of sizes — the larger the size range, the higher the Reynolds number. In this satellite image, sediment highlights these eddies in shades of turquoise, showing off the complexity of the flows created where rivers, ocean, and tides meet. The eddies we see here stretch from kilometers in width down to a handful of meters, but the flow’s turbulence persists down to millimeter-scales before viscosity damps it out. (Image credit: L. Dauphin; via NASA Earth Observatory)
I’m constantly fascinated by the intersections of art and fluid mechanics. In this video, we get an inside look at a French atelier making artist-grade pastels using centuries-old methods. And although the final product doesn’t appear to have much to do with fluids — compared to, say, paint — the process behind each pastel involves a lot of fluid mechanics: mixing, pressing, drying, and rolling. It’s a neat look at how a niche product gets made. (Video and image credit: Business Insider)
P.S. – Next week we’ll kick off our Paris Olympics coverage, but if you’d like a head start on the celebration, you can find our coverage of previous Olympics here. – Nicole
Like schools of fish, starlings gather in massive undulating crowds. Known as murmurations, these gatherings are a type of collective motion. Scientists often try to mimic these groups through simulations and lab experiments where individuals in a swarm obey simple rules that depend only on observing their neighbors. It requires very little, it turns out, to form swarms that move in this beautiful manner! (Video and image credit: J. van IJken; via Colossal)
Since Harold Edgerton’s experiments with stroboscopic photographs in the 1930s, we’ve been fascinated by the shape of splashes. These days students and artists can take advantage of programmable external flashes to capture this split-second moment of impact. Here, a pink-dyed drop of ethanol strikes a jet rising from a pool of glycerin, milk, and food coloring. The resulting splash is umbrella-like, with a thickened rim that shows tiny ligaments of fluid — an early sign of the instability that will ultimately detach droplets from the splash. This image was taken by students in a course that connects art and fluid mechanics. (Image credit: L. Sharpe et al.; via Physics Today)