Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
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…
Daily Fluids, Part 1
Just getting cleaned up and ready for the day involves a lot of fluid physics. Here are a few of the phenomena you may see daily without realizing: Plateau-Rayleigh Instability This behavior is responsible for the dripping of your faucet. More specifically, it’s the reason that a falling jet breaks up into droplets. It works…
A Day in the Life of a Fluid Dynamicist
Today I’m sharing one of my favorite videos from last year’s Gallery of Fluid Motion. It’s a short film entitled “A Day in the Life of a Fluid Dynamicist.” Although some parts of it probably only apply to fluid dynamicists (Navier-Stokes equations, anyone?) a lot of the activities depicted are common to everyone. The film…
Vortices in the Wind
Heard Island, a remote patch of rock in the southwestern Indian Ocean, peeks its head above the marine cloud layer. The volcanic island disrupts the atmosphere enough to generate a von Karman vortex street, a line of alternating vortices shedding from either side of the island. Usually these vortices would march in a straight line…
Visualizing Smell
Every day we’re surrounded by an invisible world of smells. Like the fluorescein dye in the animation above, these odors drift and swirl in the background flow. What you may not have stopped to consider when you smell the roses, though, is how the very act of sniffing changes the scent. When you inhale, filaments…