-
aamukherjee Entropie -
alchymista Alchymista -
crownedrose Hymn To The Sea -
epistemophobiarunsdeep Falling Over Myself. -
expose-the-light Quarks to Quasars -
ikenbot cwl -
pieceinthepuzzlehumanity This Is The Right One -
project-argus Hello, Universe. -
torgothegreat God Delusion
Many factors can affect the size and shape of the splash when an object impacts water and wettability—the ability of a liquid to maintain contact with a solid—is one of them. Here a sphere coated in a hydrophobic (water-repellent) nano-layer impacts water, creating a large air, streaky air cavity and a substantial splash. Contrast this with the behavior of a hydrophilic sphere entering the water, and you can imagine divers might want to invest in some hydrophilic coatings prior to the London Olympics. (Video credit: L. Bocquet et al)
ikenbot
crownedroseThere is no CG in the video above. What you’re seeing is pure, awesome science.
The black liquid mixture is known as a ferrofluid, and is made up of nano-sized, iron-containing particles suspended in water or an organic solvent. When a magnetic field is applied, the ferrofluid puffs out, creating some alien-looking shapes and formations.
Originally discovered in the 1960s at NASA, ferrofluids have found many modern uses. They form liquid seals around the spinning drive shafts of hard disks, dampen unwanted resonances to help improve the sound quality of loudspeakers, and have even found their way into museum art exhibits.
In this gallery, Wired takes a look at some of the best videos, both artistic and scientific, featuring these magical ferrofluids.
Above Video: A beastly black creature rises out of a ferrofluid lake in this video, created by artist Paul Brenner.
The Weird and Beautiful World of Fluid Dynamics
Fluids and gases can move in strange and mysterious ways that aren’t always apparent to our unaided eyes. It’s only with the use of tracers or dyes, photographic techniques and a bit of luck, that we can capture fluid dynamics in action. Here are some of the weird and beautiful ways in which fluids flow.
expose-the-lightWhen a falling liquid jet hits a horizontal impacter, it is deflected into a sheet. The shape of the sheet is dependent upon the velocity of the jet and the viscosity of the fluid. At sufficiently high speeds the sheet will be circular; at lower speeds it may sag into a bell-shape. The circular sheets can also develop an instability that causes them to become polygonal, as shown in the photos above. The fluid then flows out along the sheet, into and along the rim, and then spouts outward in jets at the polygon’s corners. For some conditions, the jets at the corners even from a sort of fluid chain (top photo). (Photo credit: R. Buckingham and J. W. M. Bush; via 14-billion-years-later)
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)
Cavitation, seen here created by a propeller, is when fluid under force develops an area of low pressure lower than the liquid’s vapor pressure. This causes the liquid to convert to gaseous form in these areas and create a cavity that rapidly collapses. This collapse generates a small shock wave that causes significant damage to metal via metal fatigue and as such cavitation is usually undesirable. However cavitation isn’t always bad and has lead to a more efficient method of marine transport using super-cavitation. In super-cavitation the object moving through the water develops such a large low pressure area that it becomes enveloped in the vapor phase, significantly lowering skin drag.
