Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
The Vibrating Network
We’ve seen the Faraday instability on vibrating fluids (and granular materials) before. Here researchers explore the effect on a a network of fluid-filled cells. Each square is filled with liquid and small holes near the bottom of each cell ensure the liquid levels are the same throughout the array. Then the entire container is vibrated.…
Inky Vortex
Ink released into water shows the swirling motion inside a vortex ring as well as its deformation and breakup upon stagnation against a wall. Although humans are known to make such vortex rings with smoke or bubbles, they are common in nature as well. Buoyant plumes often feature vortex rings at their head; dolphins and…
Labyrinth
A labyrinthine pattern forms in this timelapse video of a multiphase flow in a Hele-Shaw cell. Initially glass beads are suspended in a glycerol-water solution between parallel glass plates with a central hole. Then the fluid is slowly drained over the course of 3 days at a rate so slow that viscous forces in the fluid are…
“Cascades”
Ryan Teague’s “Cascades” music video features the enchanting process of ice growth. A chamber full of supercooled water vapor subject to a strong electric field is stimulated to grow crystals by providing a needle as the initial nucleation site. Because the vapor is supercooled, it will freeze upon contact with the nucleation site; the electric…
Viscous Dripping
Artist Skye Kelly’s “Creep (strain)” sculpture shown above is made from toffee. The viscous fluid deforms under the force of gravity, resulting in elongated drips and slow jets that buckle and coil upon reaching the floor. (Photo credits: Skye Kelly; via freshphotons)
Why Tacoma Narrows Bridge Fell
We’ve talked about aeroelastic flutter and the demise of the Tacoma Narrows Bridge before, but this explanation from Minute Physics does a nice job of outlining the process simply. As noted in the video, the common explanation of resonance is inaccurate because the wind was constant, so there was no driving frequency for the system. (In contrast, consider vibrating…
Antibubbles
Antibubbles–a liquid droplet surrounded by a thin film of gas and immersed in more liquid–are fragile things. This video explores how antibubbles behave when placed in proximity to a tornado-like whirl. When placed near the eye, where fluid motion is primarily vertical, the antibubble is stretched vertically. When placed in the rotating eyewall, the antibubble…
Fractal Fluids
These images from a numerical simulation of a mixing layer between fluids of different density show the development and breakdown to Kelvin-Helmholtz waves. The black fluid is 3 times denser than the white fluid, and, as the two layers shear past one another, billow-like waves form (Fig 1(a)). Inside those billows, secondary and even tertiary…
How Mosquitoes Fly in the Rain
One might think that rainfall would keep the mosquitoes away, but it turns out that rain strikes don’t bother these little pests much. Because the insect is so small and light compared to a falling raindrop, the water bounces off instead of splashing. This results in a relatively small transfer of momentum, although the mosquito…
Dancing Sands
Here a collection of dry grains are vertically vibrated, creating a series of standing waves on the surface of the sand. The shapes of these Faraday waves are dependent upon the frequency of the vibration. Despite the solid nature of sand particles, this behavior is much the same as the behavior of a vibrated fluid.