Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Pop-Pop Boats
I confess I’ve never heard of the pop-pop boat toys Steve Mould uses in this video. They feature a tank filled with water and a small source of heat in the form of a tea light candle. Together, these features generate propulsion and a distinctive popping sound from the toy. As he is wont to,…
A Forest of Ferrofluids
Ferrofluids are made up of ferrous nanoparticles suspended in a carrier fluid like an oil. Under magnetic fields, they take on an array of shapes — from pointed spikes to elaborate labyrinths — depending on the field strength and what fluids they’re surrounded by. This photographic series by Linden Gledhill captures some of that fantastic…
Spinning Off-Axis
To make a vortex in the laboratory, researchers typically set a tank on a rotating platform and allow the water to drain out a hole in the center of the tank. In that case, a vortex forms over the drain (like in your bathtub!) and remains centered over the hole. In nature, though, vortices rarely…
Particle-Filled Coatings
Pulling a solid object from a liquid bath can coat it in a thin layer of liquid. The thickness of the coating layer depends on the speed at which the object is removed. Introducing particles into the liquid bath adds a new dimension to the coating problem, namely the size of the particles. In this…
Stably Jammed
Granular materials like sand, gravel, and medications can become a rigid mass when squeezed or sheared. Even with a relatively loose packing, these materials can jam together to act like a solid if the contacts between grains no longer allow particles to shift or rotate. In this video, researchers explore how stable these jammed states…
How Wells and Aquifers Work
When rain falls, some of that water turns into run-off in storm systems but much of it seeps into the ground. What happens to that water? In most places, it joins the local aquifer, infusing the spaces between soil particles underground. In this video, Grady takes us through some of the interactions between surface water,…
“I See You”
In “I See You,” filmmaker Rus Khasanov captures fluid flows that give the screen an eye with which to gaze back at us. The textures visible in the flows are incredible at mimicking the details of a human iris. These are some seriously neat Marangoni flows. For a similar effect, check out this film of…
Asperitas Formation
In 2017, the World Meteorological Organization named a new cloud type: the wave-like asperitas cloud. How these rare and distinctive clouds form is still a matter of debate, but this new study suggests that they need conditions similar to those that produce mammatus clouds, plus some added shear. Using direct numerical simulations, the authors studied…
Surf’s Up
Surfers flock to northern Peru to enjoy what’s been called the world’s longest wave. These waves are generated by storms thousands of miles away in the Pacific and Southern Oceans. In the open water between, the waves sort themselves into groups of similar wavelength and speed. With the deep water off Peru, the large swells…
When Seeing a Flow Changes It
Adding dye to a flow is a common technique for visualization. After all, many flows in fluids like air and water are invisible to our bare eyes. But for some classes of flows — especially those driven by variations in surface tension — adding dye can have unforeseen effects. A recent study shows how true…