Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Skipping Stone Physics
Skipping stones across water has fascinated humans for millennia, but incredibly, we’re still uncovering the physics of this game today. A recent paper built and experimentally validated a mathematical model of a spinning, skipping disk. The authors found that, in order to skip, a stone needs to generate upward acceleration greater than 3.8 times gravity.…
The Intermittent Spring of Afton, WY
Yellowstone may get top billing, but Wyoming is home to more fluid dynamical wonders, like the world’s largest rhythmic spring. Located a little outside Afton, WY, Intermittent Spring — as the name indicates — runs for roughly 15 minutes, stops for the same length, then starts up again. The leading theory for this periodic flow…
Space Hurricanes
Researchers have observed their first “space hurricane” – a 1,000-km-wide vortex of plasma – in Earth’s upper atmosphere. Like conventional hurricanes, this storm featured precipitation (of electrons rather than rain), a calm eye at its center, and several spiral arms. Based on the group’s model, interactions between the solar wind and Earth’s magnetic fields drive…
Light Painting
Light streams from the branches of trees in this series from photographer Vitor Schietti. The effect is created with a combination of fireworks, long-exposure photography, and compositing. I love how the falling sparks create streaklines just like so many flow visualization diagnostics do! Follow more of Schietti’s work on Instagram. (Image credit: V. Schietti; via…
Where Does Stormwater Go?
Stormwater management is one of the biggest municipal challenges towns and cities face. Urban surfaces are largely impermeable, preventing rainwater from soaking into the ground. Instead roads, ditches, and channels collect water and, typically, divert it as quickly as possible into natural waterways. In contrast, wild landscapes tend to slow water run-off, filtering it into…
Falling Beads
Liquids flowing down a fiber can form bead-like droplets that may sit symmetrically (a) or asymmetrically (b) on the fiber. In general, the asymmetric droplets appear as surface tension increases or as the fiber diameter increases. The pattern of the droplets changes with flow rate. Within each subfigure, the flow rate increases from left to…
Reintroducing Beavers
Beavers are impressive ecological engineers and a keystone species for wetland environments. But in the UK, it’s been nearly 400 years since beavers were regularly found in the wild. In the meantime, Victorian engineering sensibilities drastically altered the landscape to quickly drain rainwater from upstream locations, which unfortunately increases flooding dangers downstream. But all of…
Rainfall Beyond Earth
Rain is not unique to our planet: Titan has methane rain and exoplanet WASP 78b is home to iron rain (ouch). A new study examines rainfall across planets from the perspective of individual rain drops. The authors examine raindrop shape, terminal velocity, and evaporation rate as a function of droplet size for a wide range…
Lava Fields From Above
Lava flows are endlessly fascinating to watch. They’re a destructive act of creation that seems in many ways familiar; after all, lava moves the same way we see other viscous fluids move. But it’s so much more extreme in its temperature, viscosity, and destructive potential. These beautiful aerial photos by photographer Thrainn Kolbeinsson show the…
Building a Water-Based Computer
Having previously tackled the “greedy” self-starting siphon, Steve Mould set out to build a water-based computer capable of adding simple numbers. To do this, he had to build logic gates capable of distinguishing concepts like AND and exclusive OR (XOR); the self-starting siphon was critical for this, diverting water down one output or another depending…