Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Instabilities on Instabilities
The world of fluid instabilities is a rich one. Combine fluids with differing viscosities, densities, or flow speeds and they’ll often break down in picturesque and predictable manners. Here, researchers explore the Rayleigh-Taylor instability (RTI), which occurs when a denser fluid sits above a less dense one (in a gravitational field). It’s an extremely common…
Surfactants and Waves
In the ocean, waves often curl over and trap air, becoming plunging breakers. How do surfactants like soap or oil affect this process? That’s the question behind this video, where researchers visualize breaking waves with differing amounts of added surfactant. In the case of pure water, the wave forms a smooth jet that curls over…
Möbius-Like Liquid Crystals
Möbius strips are nonintuitive objects. They appear multi-dimensional but are single-sided. Such topologies show up in other systems, too. Here we see a liquid crystal where molecular alignments, along with vortices in the fluid, result in tiny, three-dimensional shapes nicknamed “möbiusons,” thanks to their unusual properties. Each one is about 10 μm long. The researchers…
Sedimentation After Flooding
The new year brought California a series of atmospheric rivers that poured record amounts of water onto drought-stricken lands. While the precipitation refreshed snowpacks and reservoirs, much of it washed away as soils oversaturated. Those flows carried sediment with them, creating swirls of brown and green along the coastline. Compare the two satellite images above…
“FLOW”
We live in a world of fluids. We breathe them, move through them, and have them move in us. “FLOW” is a celebration of that pervasive motion, animated from hand-drawn artwork. It features fluid dynamics from our daily lives — a candle’s flame, breaking waves, pedestrian traffic — all the way to astronomical scales far…
A Bubble’s Path
Centuries ago, Leonardo da Vinci noticed something peculiar about bubbles rising through water. Small bubbles followed a straight path, but slightly larger ones swung back and forth or corkscrewed upward. The mechanism behind this behavior has been a matter of debate ever since, but the authors of a recent study believe they’ve nailed down the…
Leidenfrost Explosion
When a water drop hits a surface that’s much hotter than its boiling point, part of it will vaporize immediately. Depending on the temperature, this Leidenfrost effect can be a relatively gentle process — or not. Here, the surface is so hot that the entire drop is boiling before it’s even finished spreading from impact.…
The Chicxulub Impact’s Tsunami
66 million years ago an asteroid struck offshore of what is now Chicxulub near the Yucatán Peninsula in Mexico. The impact and its aftermath are widely credited with a mass extinction that wiped out 75% of plant and animal life on Earth, including non-avian dinosaurs. Since the impact occurred in shallow waters, it also generated…
A Look at Hagfish
Hagfish are the lords of slime. Their viscoelastic protection mechanism is so effective that they’ve hardly changed up their game in the past 300 million years. Instead, at the first sign of trouble, they release a mucus that rapidly expands in salt water. When attacking fish try to pull water into their gills, they get…
Optimal Bubble Clusters
With a bubble wand, it’s quite easy to create clusters of two or more soap bubbles. These clusters seem to instantly find the lowest energy state, forming a shape that minimizes the cluster’s surface area (including interior walls) for the volume of air they enclose. But mathematicians have struggled for thousands of years to prove…