Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Brown Dwarfs and Their Stripes
Brown dwarfs are neither stars nor gas giants but something in between. Our two nearest brown dwarf neighbors are roughly equivalent to Jupiter in size but about 30 times more massive. Since these objects are so dim, little is known about their structure. Do they resemble stars in their atmospheric patterns or gas giants like…
Ultrasonic Vibrations
Ultrafast vibrations can break up droplets, mix fluids, and even tear voids in a liquid. Here, the Slow Mo Guys demonstrate each of these using an ultrasonic homogenizer, a piece of lab equipment capable of vibrating 30,000 times a second. At that speed generating cavitation bubbles is trivial, and the flow induced by that cavitation…
How Wombats Make Stackable Feces
Wombats are unique among the animal kingdom for their ability to produce cubic feces approximately the size and shape of dice. Researchers found that wombats accomplish this geometric feat thanks to the structure of their intestines, which have bands of differing stiffness that run the full length of their guts. When the intestines contract, the…
“Satellike”
When watching Roman De Giuli’s “Satellike,” you may think you’re looking at satellite imagery of Earth. In reality, each sequence is a combination of watery ink and dried paint on paper. You can see some behind-the-scenes glimpses of the process and the artworks that inspired the work here. (Image and video credit: R. De Giuli;…
Microfluidic Pac-Man
Researchers are using coalescence to guide microdroplets through a miniature maze, a la Pac-Man. To steer the main droplet, they place a smaller droplet nearby in the direction they want to move. When the drops coalesce, it moves the main droplet in the target direction. By repeating the process, researchers can drive the drop through…
Snowflake Velocimetry
In our era of remote learning, students don’t always have a chance to do hands-on lab experiments in the usual fashion. But that doesn’t mean they can’t explore important flow diagnostic techniques. Here a simple smartphone video of snow falling gets turned into a lesson on particle image velocimetry, or PIV, a major technique for…
This Is Your Brain
The human brain, like an egg, consists of soft matter bathed in a fluid and encased in a hard shell. To better understand how our brains respond to sudden accelerations, researchers looked at how egg yolks behave. In a purely translational impact (Image 1), the egg yolk deforms very little. But rotational motions (Images 2…
Strings of Swirls
Von Karman vortex streets are the rows of alternating vortices shed off isolated objects interrupting a flow. Here, the volcanic peaks of Cabo Verde disrupt an atmospheric flow accustomed to an empty ocean. In a steady wind, air wraps around the volcanoes and detaches first on one side, creating a vortex, then from the other…
Viscoplastic Drop Impact
There are many materials that don’t behave exactly as a fluid or a solid, instead displaying characteristics of both. In this video, we see drops of hair gel falling into water. The gel is viscoplastic – showing some of the viscous behavior of a fluid and some of the plastic behavior (the inability to change…
Flexible Wings Aid Butterfly Flight
Butterflies are some of the oddest flyers of the insect world, given the large size of their wings relative to their bodies. That could be a recipe for inefficient flight, but a new study shows that butterflies’ large flexible wings actually help them take off quickly. When lifting their wings, butterflies use an unusual clapping…