Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Cavitation-Induced Microjets
In cavitation, tiny bubbles of vapor form and collapse in a liquid, often sending shock waves ricocheting. In most occurrences beyond the lab, cavitation bubbles aren’t a solo act; many bubbles can form and interact. This video takes a look at some of the effects of those interactions. When close together, two cavitation bubbles can…
Where Wind Meets Water
That the wind causes ocean waves is obvious to anyone who has spent time near the water, but the details of that process remain fuzzy. Many of the explanations — like the Kelvin-Helmholtz instability — only explain part of the process, usually the beginning when the waves are very small. As the waves get larger,…
How To: Ink Flow Photography
Ever wanted to try your hand at making these cool billowing ink photos? Photographer Jason Parnell-Brookes has a detailed tutorial over at PetaPixel laying out the necessary tools and set-up. I haven’t tried this out myself, but I hope to! How about you? (Image credit: J. Parnell-Brookes; submitted by clogwog)
Snowflake Still-Life
To take these high-resolution images of individual snowflakes, Nathan Myhrvold and his collaborators built a special camera. Their apparatus keeps the snowflakes chilled despite the strong illumination cast on them. It uses a 500 microsecond shutter and focus-stacking to produce incredibly detailed portraits of these ephemeral subjects. Each snowflake’s shape is the result of the…
Solving the Teapot Effect
The teapot effect — that tendency for liquid to dribble down the outside of the spout when pouring — is a frustration to many tea drinkers. Unraveling the fluid dynamics of this phenomenon has taken various researchers decades, but a team now believe they’ve captured the problem fully. Their full mathematical description is quite dense,…
A Colorful Fire Tornado
This one definitely belongs in the do-not-try-this-yourself category, but this Slow Mo Guys video of a colorful fire tornado is pretty spectacular. Using an array of different fuels and a ring of box fans, Gav sets up a vortex of flame that transitions smoothly from red all the way to blue. As he points out…
Wet Masks Block Droplets Better
As wearing face masks for long periods has become more typical, you may have wondered whether a soggy mask offers less protection. All masks — cloth, surgical, and N-95s — get moist from their wearer’s breath. A recent study indicates this isn’t a cause for alarm, though. Researchers looked at how relatively high-speed droplets (like…
Breaking Compound Ligaments
When pulled, viscous liquids stretch into ligaments that thin and then break into droplets. In this video, researchers investigate how these ligaments break up, depending on their composition. The initial views show the break-up of a water-glycerol ligament (Image 1) and an oil ligament (Image 2). By placing a water droplet inside oil, the researchers…
“In Flight”
Photographer Mark Harvey captured these stunning portraits of birds in flight. From acrobatic songbirds to soaring raptors, the images show the incredible morphology of a bird’s wing during flight. Most birds are constantly changing their wing shape to generate lift, change trajectory, and stabilize their flight. Note the separation between the flight feathers in all…
Triple Leidenfrost Effect
Droplets can skitter across a hot surface on a layer of their own vapor, thanks to the Leidenfrost effect. If two Leidenfrost droplets of the same liquid collide, they merge immediately. But that doesn’t always happen with two dissimilar liquids. A new study looks at how dissimilar Leidenfrost droplets collide. The researchers found that these…