Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
PyeongChang 2018: Skeleton
Skeleton, the sliding event in which athletes race down an ice track head first, is a fast-paced and punishing sport. Skeleton racers can reach speeds of 125 kph (~80 mph) during their descents. This is a little slower than the feet-first luge, in part because the skeleton sled runs on circular bars rather than sharp…
PyeongChang 2018: Ski Jumping
No winter sport is more aerodynamically demanding than ski jumping. A jump consists of four parts: the in-run, take-off, flight, and landing. The in-run is where an athlete gains her speed, and to keep drag from slowing her down, she descends in a streamlined tuck that minimizes frontal area. The biggest aerodynamic challenge comes during…
PyeongChang 2018: Moguls
Moguls are bump-like snow mounds featured in freestyle skiing competitions and also frequently found on recreational ski courses. Although competition runs are man-made, most mogul fields form naturally on their own. As skiiers and snowboarders carve S-shaped paths down the slope, their skis and snowboards remove snow during sharp turns and deposit it further downhill.…
PyeongChang 2018: Ice’s Watery Sublayer
The Olympic Charter declares that winter sports must be practiced on snow or ice. Both are frozen forms of water, which despite its ubiquity, is one of the strangest substances around. In addition to its tendency to expand as it freezes, ice is inherently slippery, and no one’s quite certain yet why. Most people have…
“Moving Creates Vortices and Vortices Create Movement”
A new interactive installation by the Japanese art collective teamLab uses the movement of visitors to drive vortex motion. Entitled “Moving Creates Vortices and Vortices Create Movement,” the installation uses projectors in a mirror room to create the sensation of an infinite, indoor ocean that’s constantly churned by the paths visitors take. In the absence of…
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…