Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Glass Isn’t a Fluid
Mark R writes: Glass is a Fluid, Too Post complex equations regarding how long it would take a certain window to flow, and post pictures of sunken glass. This would be educational. This is a pretty widespread myth. Actually, glass is not a fluid and does not behave like one as long as it is…
Surface Tension Instability
Droplets of oleic acid spread across a thin film of glycerol on a silicon wafer. The shapes here are driven by hydrodynamic instabilities, particularly Marangoni effects due to the differences in surface tension between the two fluids. (Photo credit: A. Darhuber, B. Fischer and S. Troian)
Atomizing Jets
The breakup of impinging jets into droplets (also called atomization) and the subsequent dynamics of those droplets are important in applications like jet and rocket engines where the mixing of liquid fuel with oxygen is necessary for efficient combustion. This video showcases recent efforts in high fidelity numerical simulation and modeling of such flows. The…
Brinicles
In the frozen reaches of our planet, the atmosphere and ocean can interact in bizarre ways. Under calm ocean conditions when the air at sea level is much colder than the water temperature brinicles–the underwater equivalent to an icicle–can form. The cold air above rapidly freezes ocean water at the surface, concentrating water’s salt content…
Testing Flames in Space
In microgravity, flames behave very differently than on earth due to a lack of buoyant forces. On earth, a flame can continue burning because, as the warm air around it rises, cooler air gets entrained, drawing fresh oxygen to the flame. In microgravity, both the heat from the flame and the oxygen it needs to…
Wave-Particle Duality in Bouncing Droplets
A droplet atop a vibrating pool is prevented from coalescing by the constant influx of air into a thin lubrication layer between it and the pool. But that is not the strangest aspect of its behavior. Researchers have found that this system demonstrates some aspects of the mind-bending wave-particle duality at the heart of quantum…
Ink Sculptures
Dripping ink into water can create fantastic structures as the two fluids mix. In this artwork there are numerous complex mixing phenomena: the eddies and multiple scales of turbulence; the long, thin streams of laminar flow; and the wispy mushrooms and umbrellas of the Rayleigh-Taylor instability. (Photo credit: Mark Mawson; via @thinkgeek)
Water Balloon Physics
[original media no longer available] This video explores some of the physics behind the much-loved bursting water balloon. The first sections show some “canonical” cases–dropping water balloons onto a flat rigid surface. In some cases the balloon will bounce and in others it breaks. The bursting water balloons develop strong capillary waves (like ripples) across…
Underwater Plumes
During 2010’s Deepwater Horizon oil spill there were reports of underwater plumes of oil escaping collection. This video demonstrates how such a plume can form. There are two clips shown here; in both the tank is filled with salt water of varying salinity, with denser saltwater at the bottom. The first jet is a green…
Cavity Collapse
When a solid object is driven into a quiescent liquid, a cavity is formed. As the cavity collapses jets–a type of singularity–form. In this video, researchers explore the effect of the geometry of a disk being driven into water on the shape of the cavity formed and how it collapses. As in this video of droplet…