NASA’s Solar Dynamics Observatory has found evidence of Kelvin-Helmholtz waves in the sun’s corona. These waves, which occur between two fluids of different densities or moving at different speeds, are similar to the iconic waves surfers ride. Researchers suspect that this turbulent motion may help explain why the corona is 1,000 times hotter than the surface of the sun. #
Tag: Kelvin-Helmholtz instability
Upside-Down Umbrellas
When a heavier fluid is suspended over a lighter fluid (as with ink or food coloring in water), the interface between fluids is subject to the Rayleigh-Taylor instability. As the heavier fluid starts to sink, it forms “fingers”, which develop into mushroom-cap shapes as the fluid continues falling. Sometimes the shear stress between the heavier fluid and lighter fluid causes secondary Kelvin-Helmholtz instabilities as well. (Photo by Leonardo Aguiar)
Kelvin-Helmholtz Instability
The Kelvin-Helmholtz instability occurs when velocity shear is present in a single fluid or when two different fluids have a velocity difference across their interface. As shown in this numerical simulation, the instability produces a fractal-like pattern of eddies turning over on themselves. The Kelvin-Helmholtz instability is commonly found in nature between cloud layers. #
ETA: It looks like animated GIFs may not work with Tumblr. Be sure to click on the picture to see the animation on Wikipedia.
Jupiter and the Kelvin-Helmholtz Instability
Jupiter, known for its colorful bands of stormy clouds, is a beautiful subject for fluid dynamics in action. As the planet turns, the cloud bands move at different relative speeds. This velocity difference at the interface of the bands can trigger the Kelvin-Helmholtz instability, resulting in a line of whorls where the cloud bands meet. The instability has been observed on Saturn and is thought to be fairly common among gas giants.
