Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
How Cats Drink
While humans use suction and dogs scoop water using their tongues*, cats use a dainty fluid mechanism to drink. Researchers used high-speed video to find that cats drink by touching the surface of their tongue to the water and drawing their tongue rapidly back into their mouth. Friction between their tongue and the water creates…
Turbulence Near the Wall
This photo shows a flow visualization of a turbulent boundary layer at Mach 2.8. The direction of flow is from right to left. In nature, the boundary layer between a surface and a fluid is usually turbulent but impossible to see. The visualization represents an instantaneous snapshot of the flow. Turbulence is known for its…
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. #…
Physics Tattoos
This is a man with great commitment to fluid dynamics. He writes: This, on my leg, is the incompressible form of the conservation of mass equation in a fluid, also known as the continuity equation. When people ask what it means, I say it defines flow. Sometimes I say it means you should have studied…
The Leidenfrost Effect
The Leidenfrost effect occurs when a liquid comes in contact with a mass significantly hotter than the liquid’s boiling point. Upon contact, a thin layer of the liquid will be vaporized, forming a lubricating gas layer that temporarily insulates the hot mass from the cold liquid. This effect is responsible for water skittering across a…
Flutter and the Tacoma Narrows Bridge
Sixty years ago yesterday the original Tacoma Narrows Bridge (a.k.a. Galloping Gertie) collapsed as a result of aeroelastic flutter during 42 mph winds. Flutter is a phenomenon in which the fluid dynamics and structural dynamics of a system are closely coupled, in this case resulting in a dramatic failure. The high sustained winds provided an…
Reader Question
loscheiner asks: So the video about the ooblek was clearly filmed at CU Boulder. Do you go to school here? Also, you should enable disqus comments or replies to your posts! Nope! I have connections to three different universities (one of which has been featured here), but none of them is CU Boulder. I just found…
Protecting an Egg with Oobleck
Using non-Newtonian fluids as “liquid armor” is an active area of research and development. Here students demonstrate the efficacy of shear-thickening as a defense against sudden impact by dropping a bag of oobleck containing a raw egg from different heights.
Ferrofluid Art
Hi there, Regarding ferrofluids, check out these lovely picture via Linden G. Her flickr photostream is full of beautiful ferrofluid pics. http://www.flickr.com/photos/13084997@N03/5134495790/ His photostream does have some lovely ferrofluid shots as well as some water figures. I especially like the surrealism of this one. Thanks for sharing!
Morpho Towers
Artists Sachiko Kodama and Yasushi Miyajima use ferrofluids and magnetic fields to create their “Morpho Towers – Two Standing Spirals” artwork. Ferrofluids are formed from a suspension of ferrous material in a oil or water and are a popular subject for fluid dynamics as art. You can even make your own ferrofluid at home. (via…