Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Centrifugal Instability
When it comes to geophysics, there are all kinds of phenomena that depend on rotation. In this short video, researchers demonstrate one such phenomena — the centrifugal instability — in a tank on a turn table. The experiment begins once the fluid in the tank is all rotating together, like a solid body would. Then,…
Dendritic
“What happens when two scientists, a composer, a cellist, and a planetarium animator make art?” The answer is “Dendritic,” a musical composition built directly on the tree-like branching patterns found when a less viscous fluid is injected into a more viscous one sandwiched between two plates. Normally this viscous fingering instability results in dense, branching…
Bright Volcanic Clouds
Every day human activity pumps aerosol particles into the atmosphere, potentially altering our weather patterns. But tracking the effects of those emissions is difficult with so many variables changing at once. It’s easier to see how such particles affect weather patterns somewhere like the Sandwich Islands, where we can observe the effects of a single,…
Bacterial Turbulence
Conventional fluid dynamical wisdom posits that any flows at the microscale should be laminar. Tiny swimmers like microorganisms live in a world dominated by viscosity, therefore, there can be no turbulence. But experiments with bacterial colonies have shown that’s not entirely true. With enough micro-swimmers moving around, even these viscous, small-scale flows become turbulent. That’s…
How Canal Locks Work
For thousands of years, boats have been a critical component of trade, efficiently enabling transport of goods over large distances. But water’s self-leveling creates challenges when moving up and downstream through rivers and canals. To get around this, engineers use locks, which act as a sort of gravity-driven elevator to lift and lower boats to…
Fluorescent Dancing Droplets
These fluorescent droplets of glowstick liquid jiggle and dance in a solution of sodium hydroxide. Some droplets jitter. Some rotate. And some undergo one coalescence after another. It’s always fun to see how fluid dynamics and chemistry combine! (Image and video credit: Beauty of Science)
Why Slicing Tomatoes Works
Picture it: a nice, ripe tomato. Your not-so-recently sharpened kitchen knife. You press the blade down into the soft flesh and… it explodes. Soft solids – like a tomato – don’t react well to cutting, but they slice just fine. Examining why that’s the case is at the heart of this model. Tomatoes are essentially…
Why Aren’t Trees Taller?
Trees are incredible organisms, with some species capable of growing more than 100 meters in height. But how do trees get so big and why don’t they grow even taller? The limit, it turns out, is how far fluid forces can win over gravity. To live and grow, trees must be able to transport nutrients…
Two Views of Ocean Eddies
Colorful, sediment-laden eddies swirl off the Italian coast in this satellite image. These small-scale eddies — less than 10 km in diameter — can be short-lived and are often difficult to capture in numerical models, but remote sensing can help scientists better understand their impact on oceanic mixing, especially when we capture more than one…
Shear in Shaken Sands
The dynamics inside a shaken granular material, like sand, are fascinatingly complex. In this study, researchers used x-ray radiograms to peer inside a horizontally-shaken container of sand. They found that the sand soon formed bands of lower density (seen as yellow in the radiogram) near the center of the container. Because these bands show a…