Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
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Supercritical Fluids
Supercritical fluids live in the region of a phase diagram beyond the critical point. At these temperatures and pressures, a substance is neither strictly liquid nor a gas but exhibits behaviors from both. A supercritical fluid can effuse through a solid like a gas does but can also dissolve substrates like a liquid. As noted…
Freezing Soap Bubbles
This is what it looks like when a soap bubble freezes. Perhaps not strictly fluid mechanical in nature, but it’s a nice thermodynamics demonstration.
Saturnian Storm
Back in mid-December, amateur astronomers discovered an enormous new storm on Saturn. The Cassini spacecraft captured this image early in the storm’s history (it now stretches farther around the planet). The fluid dynamics of Saturn’s atmosphere are incredibly complex and well beyond our current understanding, but we can certainly appreciate the majesty of a swirling,…
Reader Question: Surface Tension vs. Viscosity
lazenby asks: How can superfluid liquid Helium have zero viscosity while retaining surface tension? (assuming something like surface tension is required for a liquid to form drops) The short answer is that surface tension and viscosity are two totally separate properties for a fluid. To illustrate how one can exist without the other in a superfluid,…
Superfluid Helium Leaks from its Container
Below a temperature of 2.17 Kelvin, helium becomes a superfluid, a state of matter boasting several unique properties including zero viscosity (resistance to flow). In this video, scientists demonstrate that property. When they pull the glass “bucket” of helium out at 2:50, the helium starts to leak out. The glass is solid but it contains…
Flying Paint
High speed footage of flying paint demonstrates a world of viscosity and surface tension, as well as another great example of fluid dynamics as art. (via Gizmodo) If you enjoy FYFD, why not take a minute to recommend us in the Tumblr directory? Thanks!
Ferrofluid Labyrinths
Here’s a different take on ferrofluids. Instead of spikes, we get 2D patterns reminiscent of these ones. Most likely the ferrofluid is trapped under glass as part of a Hele-Shaw cell. The results remind me some of chaotic Rayleigh-Benard convection cells, actually.
Butterfly Soap Spiral
A stationary soap film disturbed by a flapping foil (seen in the top center) creates a butterfly-like double spiral roll. Two vortices form at the tip of the foil each time it changes direction; look carefully and you can see those tiny vortices all the way through the spirals. (From the 2010 Gallery of Fluid…
Reader Question: Hot Air Balloon Physics
lazenby asks: and boyancy in air? is the lifting capacity of a hot air balloon equal to the modulo of the weight of the air in the balloon with the weight of the same volume of air outside the balloon? for that matter, does the lift of a big helium weather balloon decrease as air pressure,…
The GE Show
[original media no longer available] While this video is not strictly about fluid dynamics, there are some pretty cool high-speed fluids moments in it. Watch the reaction of the gelatins as objects hit them and observe the deformation of the water balloons as they strike. (via JetForMe)