Twisting in the Flow

What happens to liquid crystals in a flow? In this video, researchers look at liquid crystals flowing through the narrow gap of a microfluidic device. Initially, all the crystals are oriented the same way, as if they are logs rolling down a river. But as the flow rate increases, narrow lines appear in the flow, followed by disordered regions, and, eventually, a new configuration: vertical bands streaking the left-to-right flow. The colors, in this case, indicate the orientation of the liquid crystals. As the researchers show, the crystals collectively twist to form the spontaneous bands. (Video and image credit: D. Jia and I. Bischofberger)

“Visions in Ice”

The glittering blue interior of an ice cave sparkles in this award-winning image by photographer Yasmin Namini. The cave is underneath Iceland’s Vatnajokull Glacier. Notice the deep scallops carved into the lower wall. This shape is common in melting and dissolution processes. It is unavoidable for flat surfaces exposed to a melting/dissolving flow. (Image credit: Y. Namini/WNPA; via Colossal)

A Stellar Look at NGC 602

The young star cluster NGC 602 sits some 200,000 light years away in the Small Magellanic Cloud. Seen here in near- and mid-infrared, the cluster is a glowing cradle of star forming conditions similar to the early universe. A large nebula, made up of multicolored dust and gas, surrounds the star cluster. Its dusty finger-like pillars could be an example of Rayleigh-Taylor instabilities or plumes shaped by energetic stellar jets. (Image credit: NASA/ESA/CSA/JWST; via Colossal)

Learned Helplessness
https://wp.me/p84YjG-4Nn
#helplessness #zsoltzsemba #indonesia #poverty #middleclass #instability #jobmarket #kerja #miskin #edukasi #community #zsoltzsemba

https://zsoltzsemba.com/2025/03/22/learned-helplessness/

“The Ballet of Colors”

Thomas Blanchard’s short film “The Ballet of Colors” plunges viewers into a warm spectrum of roiling oil and paint. Fluid dynamically speaking, it could be subtitled “the Plateau-Rayleigh instability” thanks to its focus on retracting paint ruptures and ligaments breaking into droplets. Unlike some other videos of this genre, Blanchard uses a high-speed camera here, filming the action at 1,000 frames per second, and the result is smooth, crisply focused, and absolutely delectable. (Video and image credit: T. Blanchard et al.)

Ultra-Soft Solids Flow By Turning Inside Out

Can a solid flow? What would that even look like? Researchers explored these questions with an ultra-soft gel (think 100,000 times softer than a gummy bear) pumped through a ring-shaped annular pipe. Despite its elasticity — that tendency to return to an original shape that distinguishes solids from fluids — the gel does flow. But after a short distance, furrows form and grow along the gel’s leading edge.

Since the gel alongside the pipe’s walls can’t slide due to friction, the gel flows by essentially turning itself inside out. Inner portions of the gel flow forward and then split off toward one of the walls as they reach the leading edge. This eversion builds up lots of internal stress in the gel, and furrowing — much like crumpling a sheet of paper — relieves that stress. (Image and research credit: J. Hwang et al.; via APS News)

#Trump’s senior advisers downplayed fresh economic turbulence Monday as the admin’s escalating #TradeWar deepened a sell-off on #WallStreet & renewed fears about the stability of the US #economy.

As all 3 major US #stock indexes slumped, Trump’s team projected confidence that the volatility would prove temporary & that an economic boom set off by tax cuts [for #corporations & the #wealthy] would follow later this year.

#tariffs #instability #finance #USpol #trumpcession
https://www.washingtonpost.com/business/2025/03/10/stocks-dow-fall-trump/

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)

The Trump administration's quest to expand the president's #firing #authority over members of #independent #agencies paints a target on the #FederalEnergyRegulatoryCommission that would create #instability within the #energy #industry if at-will removal of #commissioners becomes a reality. [via email from Law360]
#USA #Trump

Instabilities in Competition

When two liquid jets collide, they form a thin liquid sheet with a thicker rim. That rim breaks into threads and then droplets, forming a well-known fishbone pattern as the Plateau-Rayleigh instability breaks up the flow. This poster shows a twist on that set-up: here, the two colliding jets vary slightly in their velocities. That variability adds a second instability to the system, visible as the wavy pattern on the central liquid sheet. The sheet’s rim still breaks apart in the usual fishbone pattern, but the growing waves in the center of the sheet eventually that structure apart as well. (Image credit: S. Dighe et al.)

The Mystery of the Binary Droplet

What goes on inside an evaporating droplet made up of more than one fluid? This is a perennially fascinating question with lots of permutations. In this one, researchers observed water-poor spots forming around the edges of an evaporating drop, almost as if the two chemicals within the drop are physically separating from one another (scientifically speaking, “undergoing phase separation“). To find out if this was really the case, they put particles into the drop and observed their behavior as the drop evaporated. What they found is that this is a flow behavior, not a phase one. The high concentration of hexanediol near the edge of the drop changes the value of surface tension between the center and edge of the drop. And that change is non-monotonic, meaning that there’s a minimum in the surface tension partway along the drop’s radius. That surface tension minimum is what creates the separated regions of flow. (Video and image credit: P. Dekker et al.; research pre-print: C. Diddens et al.)