Plate Nº 59 · recorded October 10, 2026
PhysicsReported finding
Whirlpool Lab Captures Kelvin-Wave Turbulence First Predicted in 1880
For the first time, physicists have directly filmed Kelvin-wave turbulence on a tabletop water vortex, confirming Lord Kelvin's 1880 prediction. The measured ripples cascade across a factor of 100 in size.
By Nathan Brooks3 min read605 words
In brief
- Published September 24, 2026 in Physical Review Letters; led by Eric Falcon at Université Paris Cité, with Jason Barckicke as lead author.
- Lord Kelvin first described the ripples mathematically in 1880, roughly 150 years before the experiment.
- Energy spread across a range of ripple sizes spanning roughly a factor of 100, matching Kelvin-wave turbulence theory.
- Measurements identified a six-wave interaction mechanism, the exact process Kelvin's framework predicts.
- The setup could become a versatile room-temperature laboratory for studying Kelvin waves in contexts from superfluids to neutron stars.
In a cylindrical tank of draining water, physicists have directly observed a form of wave turbulence first predicted in 1880, confirming with experiment a theory that has shaped thinking about superfluids and neutron stars for nearly 150 years.
The work, published on September 24, 2026 in Physical Review Letters by a team led by Eric Falcon at Université Paris Cité, finally puts images to an idea that Lord Kelvin, a Scottish physicist, described mathematically in 1880. The lead author of the paper is Jason Barckicke.
What is Kelvin-wave turbulence?
Kelvin waves are corkscrew-shaped ripples that travel along the core of a vortex, the spinning column at the heart of a whirlpool. When many Kelvin waves coexist on the same vortex, Kelvin's theory predicts that they pass energy along a cascade: large, slow ripples hand off energy to ever smaller, faster ripples, until the energy finally dissipates as sound.
For decades, physicists treated this cascade as a leading explanation for how turbulence dies away in superfluids. These are exotic liquids cooled to within a fraction of a degree of absolute zero, where they flow without any friction.
Stir such a liquid and its rotation concentrates into tangles of extremely thin vortices, sometimes just fractions of a nanometer wide. As those vortices cross and reconnect, they launch Kelvin waves. The resulting cascade is thought to be how a superfluid's turbulence eventually fades.
The trouble is tracking those ripples. In helium superfluids the vortices are too thin to film directly, and the waves move too fast. So Falcon's group turned to something much larger: an ordinary water vortex in a lab tank.
How did the team see it?
The researchers continuously pumped water into a cylindrical tank and let it drain through a small hole at its base, producing a long, steady vortex. A ring placed at the top of the vortex gently shook its upper end in a random pattern, injecting energy into the system.
A high-speed camera then filmed the vortex core along much of its length, letting the team track exactly how it moved in both space and time. The setup let the team study Kelvin waves at scales far easier to measure than those in a superfluid, but governed by the same underlying physics.
What did the measurements show?
The footage revealed the predicted cascade. Energy supplied by the shaking ring spread from large, slow ripples into smaller, faster ones, over a range of ripple sizes spanning roughly a factor of 100. The distribution of that energy matched predictions from Kelvin-wave turbulence theory.
The team also pinpointed the mechanism behind the transfer. The ripples exchanged energy in groups of six waves at a time, the exact six-wave interaction Kelvin's framework had specified. Falcon's group describes the result as long-awaited experimental support for ideas that physicists have developed over several decades.
Why does this matter?
The result does more than validate a 19th-century equation. The team's tank now serves as a versatile, room-temperature laboratory for studying Kelvin waves, where researchers can vary parameters far more easily than in a cryogenic superfluid experiment.
Falcon's team expects that more precise versions of the setup will let researchers explore more complex scenarios, such as many vortices interacting at once. That work could help physicists model turbulence in systems as different as laboratory superfluids and the interiors of neutron stars, where superfluid matter is thought to swirl in the cores of collapsed stars.
The paper's DOI is 10.1103/t3bt-m431; a preprint is available on arXiv at arxiv.org/abs/2607.07535.
via Phys.org Physics (Source)
More from Nathan Brooks
Nearby plates
- Jet Diffusion Wakes Detected in Quark-Gluon Plasma, 20 Years On
- Picosecond Pulses Push Superconductors Past Their Vortex Limit
- NSF commits $90 million to three new science and technology centers
- Dead Star Powers a 1,000-Year Shock Wave It Shouldn't Be Able to Make
- Physicists bridge ultraslow spin glasses and ultrafast black-hole math