Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Arriving at Jupiter
Today all eyes turn to Jupiter where NASA’s Juno spacecraft will enter orbit around the gas giant. In preparation, Hubble and ground-based telescopes have been observing Jupiter in both the visible (upper right) and infrared (upper left) spectrum. The lower image shows a 1:5 scale model of Juno and a full-size replica of one of…
Easy Squeezing
Nearly everyone has struggled with the frustration of trying to get ketchup, toothpaste, or peanut butter out of a container. These fluids and fluid-like substances are notoriously difficult to budge because they prefer to wet and adhere to solid surfaces. One way to limit this adhesion is to use a superhydrophobic surface, like the one…
Denticles and Sharkskin
Look closely enough at a shark’s skin, and you will find it is covered in tiny, anvil-shaped denticles (lower left). To try and discover how and why these denticles help sharks, researchers are 3D printing denticles in different patterns onto flexible sheets to create biomimetic shark skin (lower right). They test the artificial shark skin…
Resonating Bowls
Rub your hands on the handles of a Chinese resonance bowl and you can generate a spray of tiny droplets. The key to this, as the name suggests, is vibration. Rubbing the handles vibrates the bowl, causing small oscillations in the bowl’s shape that are too small for us to see. But those vibrations do…
Rayleigh-Taylor Waves
Here on Earth, placing a denser fluid over a lighter one creates an unstable equilibrium. Thanks to gravity, the heavier, denser fluid wants to sink and the lighter fluid wants to rise. Any small disturbance will kick this into action, just like a tiny nudge can send a ball rolling down the hill. For the…
Reader Question: Splashes
Reader effjoebiden asks: So is the crown splash the curving wave of water on either side of the tire, the spikes of water in the middle behind the tire, or both? And is the Worthington jet also the same phenomenon that can happen with a massive meteorite impact? Here the term “crown splash” refers to the…
Sublimation
Sublimation is a transition directly from a solid phase to a gaseous one. Given typical Earth atmospheric conditions, one of the most commonly observed examples of sublimation is that of solid carbon dioxide, a.k.a. dry ice. Submerging dry ice in water both speeds up the sublimation–since water is a better conductor of heat than air–and…
Daily Fluids, Part 4
Inside or outside, we encounter a lot of fluid dynamics every day. Here are some examples you might have noticed, especially on a rainy day: Worthington Jets After a drop falls into a pool, there’s a column-like jet that pops up after it and sometimes ejects another small drop. This is known to fluid dynamicists…
Daily Fluids, Part 3
A lot of the fluid dynamics in our daily lives centers around the preparation and consumption of food. (And in its digestion afterward, but that’s another story!) Here are a few examples of fluid dynamics you might not have realized you’re an expert on: Low Reynolds Number Flows This is a fancy way of discussing…
Daily Fluids, Part 2
We play with fluid dynamics all the time, though we don’t always think of it as such. Here are a few ways it shows up in the ways we play: Aerodynamics This is the study of air moving past an object. Whether you’re throwing a paper plane, flying a kite, or riding a bike, aerodynamics…