When instabilities exist in laminar flow, they do not always lead immediately to turbulence. In this video, a viscous fluid fills the space between two concentric cylinders. As the inner Keep reading
Month: November 2024
“Compressed 02”
This timelapse video shows the spreading of food coloring and a ferrofluid through soap suds surrounding a magnet. Capillary action, the same force that enables sap to flow up through Keep reading
Aircraft Contrails
[original media no longer available] Under the right atmospheric conditions, condensation can form, even at low speeds, as moist air is accelerated over airplane wings. This acceleration causes a local Keep reading
Hurricane Irene
This August 25th satellite image shows Hurricane Irene over the Bahamas and Florida. Hurricanes are fueled largely by the release of heat as warm water vapor in the rising air Keep reading
The Barus Effect
Non-Newtonian fluids are full of all kinds of unusual behaviors. Here a highly viscoelastic non-Newtonian fluid exhibits the Barus effect, in which extruding the fluid causes the falling jet to Keep reading
Bursting Bubbles
A soap bubble bursts when its surface tension is broken, and, although from our perspective, the bubble bursts instantly, the process is actually directional. The bubble disintegrates from the point Keep reading
Sound and Harmonics
The vibrations we perceive as sound, whether in air, water, or any other fluid, are tiny pressure waves emanating from a source, transmitting like ripples across a pond, and finally Keep reading
Simulating Turbulence
Turbulent flows are complicated to simulate because of their many scales. The largest eddies in a flow, where energy is generated, can be of the order of meters, while the Keep reading
Feynman: The Universe in a Glass of Wine
Some wisdom for you this Friday from the incomparable Richard Feynman: A poet I think it is who once said the whole universe is in a glass of wine. I Keep reading
How Coffee Rings Form
Coffee rings (an ubiquitous feature of academia) are formed by the deposition of particles as the liquid evaporates. When a coffee drop evaporates, capillary action draws the coffee particles toward Keep reading