The Wet-Dog Shake: How wet mammals dry themselves

The drying of wet fur is a critical to mammalian heat regulation. This fluid dynamics video demonstrates how hirsute animals rapidly oscillate their bodies to shed water droplets, nature's analogy to the spin cycle of a washing machine.

High-speed videography and fur-particle tracking is employed to determine the angular position of the animal's shoulder skin as a function of time. X-ray cinematography is used to track the motion of the skeleton. Particular attention is paid to rationalizing the relationship between animal size and oscillation frequency required to self-dry.

http://arxiv.org/abs/1010.3279, ArXiv, 15 Oct 2010

How do jellyfish eat?

Video of the pulsing dynamics and the resulting fluid flow generated by the upside down jellyfish, Cassiopea spp. Medusae of this genus are unusual in that they typically rest upside down on the ocean floor and pulse their bells to generate feeding currents, only swimming when significantly disturbed. The pulsing kinematics and fluid flow around these upside down jellyfish is investigated using a combination of videography, flow visualization, and numerical simulation. Coherent vortex rings are not seen in the wake above the jellyfish, but starting and stopping vortices are observed before breaking up as they pass through the elaborate oral arms (if extended). Feeding Currents Generated by Upside Down Jellyfish, ArXiv, 16 Oct 2010

Floating water bridge between two beakers

The interaction of electrical fields and liquids can lead to phenomena that defies intuition. Some famous examples can be found in Electrohydrodynamics as Taylor cones, whipping jets or non-coalescing drops. A less famous example is the Floating Water Bridge: a slender thread of water held between two glass beakers in which a high voltage difference is applied. Surprisingly, the water bridge defies gravity even when the beakers are separated at distances up to 2 cm. "Building water bridges in air: Electrohydrodynamics of the Floating Water Bridge", ArXiv, 19 Oct 2010.