Schlieren photography is a common experimental flow visualization technique, especially in supersonic flows (where it enables one to see shock waves). Here the Science Channel’s “Cool Stuff: How It Works” show explains the technique and shows some examples from everyday life.
Search results for: “waves”
Vibrating Oobleck
[original media no longer available]
This video explores some of the non-Newtonian behaviors of oobleck when shaken. The pattern across the surface once the vibrations start is called Faraday waves, a type of nonlinear standing wave that forms once a critical vibrational frequency is passed and the flat surface of the fluid becomes unstable. Toward the end of the video, the frequency of the vibrations is increased until “finger-like protrusions” form. This is a behavior exhibited by shear-thickening non-Newtonian fluids.
Wave Pool
This Japanese pool, lined with computer-controlled actuators, uses the principle of wave interference to create complex shapes at the center of the pool. While we may be more familiar with wave interference using light or sound, the principles remain the same for a wave in a fluid. (via Gizmodo and phredgreen)
Supersonic
Moving supersonically–faster than the local speed of sound–can cause some awesome effects. Among these are vapor cones (a.k.a. Prandlt-Glauert singularities), shock waves, and, of course, the sonic boom.
Flying Fish Aerodynamics
New research using wind tunnel measurements of (dead) flying fish is giving new insight into how these fish are able to fly over the waves. Lift and drag data indicates that flying fish have a gliding ability comparable to soaring birds like hawks! #
The Sound of Helium
Gases of different density are good for more than just physics demonstrations. They also affect the transmission of sound waves, thereby altering our perception of pitch. As fun as sulfur hexafluoride is, though, don’t go playing with it at home; it’s an extremely potent greenhouse gas.
Breaking the Sound Barrier
The shock waves propagating in front of an Atlas V rocket after launch decimate a rainbow-like effect called a sun dog. #