Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Crevasses
Glacial ice is constantly flowing but at speeds we don’t notice by eye. That doesn’t mean there aren’t signs, though! Crevasses, narrow fractures in the ice that may be tens of meters deep, are a sign of those flows. Crevasses form in areas where the ice is under high stress. That could be a spot…
Flowing Through Tight Spaces
Fluid flow through porous media inside confined spaces can be tough to predict but is key to many geological and industrial processes. Here researchers examine a mixture of glass beads and water-glycerol trapped between two slightly tilted plates. As liquid is drained from the bottom of the cell, air intrudes. Loose grains pile up along the meniscus…
Water Calligraphy
Artist Seb Lester creates calligraphy using ink and water, but not in the way you might expect. After writing in water, the artist applies ink a drop at a time, allowing fluid forces to spread it. There are a few effects at play here. Molecular diffusion – the random motion of molecules – can help…
The Drinking Bird
At first glance, the drinking bird is a simple desk toy, but the physics and engineering behind the device is clever enough to have challenged many great minds. In this video, Bill Hammack dissects the drinking bird, revealing the heat engine beneath the felt and feathers. The bird’s drinking is driven by thermodynamics and the…
Prehistoric CFD
Computational fluid dynamics (CFD) has been a valuable tool in engineering for decades, but its use is spreading to other fields as well. The image to the left shows a reconstruction of Parvancorina, a shield-shaped marine creature that lived some 550 million years ago. Fossil evidence alone cannot tell paleontologists whether this extinct creature could…
Microfluidic Legos
Microfluidic devices are valuable tools in a lab, but they are difficult and time-consuming to manufacture. Researchers looking to simplify the building of such fluidic circuits have turned to toys. The uniformity and modularity of LEGO bricks makes them a promising platform for modifiable microfluidics. Using a micromilling machine, researchers cut narrow channels into bricks,…
Scallops and Erosion
Although we often think of solids as immovable in the face of flow, the motion of air and water sculpts many parts of our world. One common pattern, seen both on surfaces that melt and those that dissolve into a flow, is called scalloping. Mathematical analysis shows that flat surfaces exposed to a flow that…
“Breathe”
In black and white, the towering power of a thunderstorm looks almost apocalyptic. Photographer Mike Olbinski’s latest storm timelapse, “Breathe,” features roiling turbulence, distant downpours, and eerie mammatus clouds. Supercell thunderstorms churn and rotate over empty horizons. Billowing cumulus clouds condense from bright skies. Flashes of lightning reveal the outlines of massive thunderheads. It’s a beautiful…
In the Eye of a Hurricane
Although eyes are common at the center of large-scale cyclones, scientists are only now beginning to understand how they form. Since real-world cyclogenesis is complicated by many competing effects, researchers look at simplified model systems first. A typical one uses a shallow, rotating cylindrical domain in which heat rises from below. The rotation provides a…
Jumping Larvae
Gall midge larvae, despite their lack of legs, are prodigious jumpers. These worm-like creatures use hydrostatic pressure to jump more than 30 body lengths. To do so, the larva curls itself into a loop, latching its mouth to its tail. It then shifts the fluids inside its body, flattening itself as the pressure builds. When…