Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Using Flow Separation to Fly
Fixed-wing flight typically favors the efficiency of long skinny wings, which is why so many aircraft have them. But for smaller flyers, like micro air vehicles (MAVs), short and stubby wings are necessary to stand up the disruption of sudden wind gusts. But a new MAV design eschews that conventional wisdom in favor of a…
In Search of a Better Espresso
Of specialty coffee drinks, espresso has the most cup-to-cup variation in quality. For those who are not coffee aficionados — such as yours truly — espresso is made by forcing hot water through a packed bed of coffee grains. Many factors can affect the final output, including the amount of dry coffee used, the fineness…
The World in a Droplet
Capturing refracted images in a droplet is a popular pastime among high-speed photographers, and in this solo Slow Mo Guy outing, we get to see that process in video. Physically, the subject is a simple drop of water, which on impact with a pool, rebounds into a Worthington jet and ejects one or more droplets…
Perfecting Giant Bubbles
Whether young or old, everyone enjoys blowing soap bubbles, and the bigger the bubble, the more impressive it is. Researchers have been on a quest to discover how bubbles can survive with volumes measured in the tens of meters and thicknesses of mere microns. The key to these behemoth bubbles are the polymer chains inside…
Where are Titan’s Deltas?
Saturn’s moon Titan is the only other planetary body in our solar system known to have bodies of liquid on its surface. But where Earth has lakes and seas of water, Titan’s are hydrocarbon-based, primarily ethane and methane. As on Earth, these liquids rain from skies and run down rivers and streams into larger bodies.…
Wild Gray Seals Clap Back
Here’s a paper that cries out for fluid dynamical/acoustical follow-up: wild gray seals have been observed signaling underwater by clapping their forefins. As you can hear in the video, the sound is quite loud and carries well underwater. The biologists who observed the behavior postulate that it’s used by males during breeding season to ward…
Collective Catfish Convection
Gather many birds, fish, or humans together and you often get collective motion that’s remarkably fluid-like in appearance. This video shows a group of juvenile striped eel catfish, an (eventually) venomous species that uses strength in numbers for protection while young. Their movement is rather mesmerizing, and if you watch individual catfish, you’ll see a…
“Otherworld, Vol. 1”
Roman De Giuli’s “Otherworld, Volume 1” is a beautiful exploration of color and flow. Glittery particulates act as tracers in the flow, reminiscent of the way rheoscopic fluids do. In many sequences, the glitter lends a sense of texture to the flow. Without context, I cannot say whether those are true flow features, but they…
Holding Fast in the Flow
Many tiny creatures in the natural world face living in fast flows. The larvae of the net-winged midge, for example, forage their way through fast-flowing Alpine springs with speeds of 3 m/s or more. You or I would find standing in such water a challenge, but these larvae are unbothered, thanks to the clever suction-cup-like…