Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Vortex Rings From a Square Outlet
When a vortex ring forms, it’s often from fluid forced through a round outlet, whether that’s someone’s mouth, a pipe, or a dolphin’s blowhole. But vortex rings can come from other shapes, too. This video shows us several examples, including slots and square outlets. The vortex rings blown from a square outlet are messier but…
Corralling Corals
So much of fluid dynamics is seeking patterns. Shown here are two sets of patterns, each created by a different species of coral larvae. These tiny creatures form a streaming flow (orange inset) around them as they swim. Combined together in a petri dish, the larvae follow winding paths, shown in white. The overall pattern…
The Sound of Bubbles
Every day I stand in front of my refrigerator and listen to the water dispenser pouring water into my glass. The skinny, fast-moving jet of water plunges into the pool, creating a flurry of bubbles. Those bubbles come from air the water jet pulls in with it, and the sound the water makes (minus the…
Liquid Lace
3D printers are a neat apparatus for exploring flow instabilities. If too much material is extruded compared to the speed of the printer head, coiling takes place. But under-extrusion creates patterns, too. Here, researchers show how under-extrusion can create a stable lace-like pattern. Once dried, the material can stretch, but only in certain directions, a…
“High Flow”
Roman De Giuli’s “High Flow” is vibrant and energetic. Colorful paints and inks flow across the page, creating complex patterns. I love the blossoming flows, feathery fronds, and spreading Marangoni effects. De Giuli’s films never disappoint! (Video and image credit: R. De Giuli)
Water Jumping Hoops
Small creatures like springtails and spiders can jump off the air-water interface using surface tension. But larger creatures can water-jump, too, using drag. Here, researchers study drag-based water jumping with a simple elastic hoop. Initially, two sides of the hoop are pulled closer by a string, deforming the hoop. Then, with the hoop sitting upright…
Miniature Ice Stupas
Ice stupas are conical artificial glaciers built with snow cannons; they’re used to store water for spring irrigation. Here, researchers explore a miniaturized lab-grown version made from atomized water droplets. The growing drop breaks and spills, forming frozen fingers in all directions. Further drops flow and freeze as rivulets atop the stupa — or they…
Drying Unaffected by Humidity
Water evaporates faster in dry conditions than in humid ones, but the same isn’t true of paint. Instead, paint’s drying time is largely independent of the day’s humidity. That’s because of paint’s long chains of polymers. As water in the paint evaporates, these polymers are drawn to the surface, forming a viscoelastic layer that hinders…
“Coat or Collapse?”
Imagine a layer of particles sitting at the interface between oil and water. Known as a granular raft, these particles can interact in interesting ways with other objects. Here, researchers experiment with allowing different shapes to fall through the raft. At slow speeds, the raft deforms to coat the object, even if it has a…
“Alive”
In “Alive,” filmmaker Christopher Dormoy explores acrylic paints and the variety of ways in which the medium can be used. From a fluids perspective, there’s dripping, viscous flow, turbulent eddies, billowing plumes, and “accidental painting” due to density-driven instabilities. It’s a fun tour of fluid phenomena in art. What examples do you spot? (Video and…