Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Reader Question: White Caps
Reader eclecticca asks: I really like the last two posts about waves, and they left me with another question… My dad had a little boat he used to take us ocean fishing on quite a bit. I always noticed that some days we just had big waves (swells) when out from the coastline and in fairly deep water (a hundred…
Ferrofluid in a Cell
Ferrofluids are a colloid consisting of magnetically sensitive nanoparticles suspended in a carrier liquid, like oil. They’re often associated with a distinctive spiky appearance when exposed to a magnet, but this isn’t their only magnetic response. Above we see a ferrofluid confined to a Hele-Shaw cell – essentially two glass plates with a small gap between them. In the upper image, the…
Reader Question: Waves Breaking
As a follow-up to the recent waves post, reader robotslenderman asks: What does it look like when the wave breaks? And why do waves sometimes push us back? Why are we able to ride them? I wasn’t able to find an equivalent breaking wave version of that dyed wave – side note: readers with flumes, please feel free…
Cavitation Collapse
The collapse of a bubble underwater doesn’t seem like a very important matter, but when it happens near a solid surface, like part of a ship, it can be incredibly destructive. This video, featuring numerical simulations of the bubble’s collapse, shows why. When near a surface, the bubble’s collapse is asymmetric, and this asymmetry creates a powerful jet that pushes through…
How Waves Travel
When playing in the surf, it’s easy to imagine that the incoming waves are a wall of water crashing into the shore. And, in a way they are, but probably less so than you imagine. Waves travel through a medium, whether it’s solid or fluid, but for the most part, they’re not translating the medium itself. You…
“Vorticity 2”
There’s no better way to appreciate our atmosphere than through timelapse, and photographer Mike Olbinski is a master at capturing the beauty and power of nature at work through this medium. In “Vorticity 2″, he highlights two full seasons of storm chasing in an incredible seven-and-a-half minutes. Prepare yourself for dramatic cloudscapes, torrential rains, and even…
Breaking Up
The dripping of a faucet and the break-up of a jet into droplets is universal. That means that the forces – the inertia of the fluid, the capillary forces governed by surface tension, and the viscous dissipation – balance in such a way that the initial conditions of the jet – its size, speed, etc. – don’t…
Feathered Fighter Jets
Peregrine falcons are built for speed. They’ve been clocked at more than 380 kilometers per hour when diving. This video from Deep Look examines some of the features that make these birds of prey so fast, from the shape of their eyes to the tubercles in their nostrils that help them breathe during high-pressure dives. Part of the…
Grayscale Aurora
This swirling grayscale image shows a spring aurora over the Hudson Bay, as seen by the Suomi NPP satellite. As energetic particles from the sun zip past Earth, they interact with our magnetosphere, which tends to channel particles toward the poles. At these higher latitudes, some of the particles get trapped along Earth’s magnetic field lines and crash into…
Splashes on Hairy Surfaces
The question of whether a droplet will splash is a complicated one, even for smooth surfaces, but researchers are also interested in what happens to hairy surfaces when droplets strike. By varying the droplet viscosity and speed, along with the spacing of the hairs, researchers sketched out the variety of impacts one can get. What…