Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
The Airbag’s Inflation
Airbags have become a standard safety feature for automobiles. As the Slow Mo Guys demonstrate in the video above, the bags inflate incredibly quickly–less than 1/25th of a second! The incredible speed of the system’s deployment is what keeps the car’s occupants from slamming into the hard surfaces of the wheel or dashboard. But this only…
Barchan Dunes
Crescent-shaped barchan dunes are common on both Earth (top image) and Mars (bottom image). They form in areas where the wind comes predominantly from one direction. As the wind blows, it deposits sand on the gently sloping windward face of the dune. The leeward face of the dune is steeper; its shape is set by…
Inside a Water Blob
This new video from the Space Station shows once again that astronauts have the most fun job on–or off–the planet. In it, the Expedition 40 crew members submerge a GoPro camera in a microgravity water blob. Here on Earth, we’re used to surface tension being a minor or secondary force with most fluids we experience…
“Milky WaY”
Photographer Paulo Stagnaro uses milk and food coloring in his series “Milky WaY”. Despite the simple ingredients, the photos illustrate the enormous variety of shape and form in fluid dynamics. Surface tension, diffusion, and intentional mixing create abstract and ephemeral portraits of fluid motion. For similar work, see Pery Bruge’s art or just try browsing through FYFD’s “fluids as art” tag for more examples of science…
Von Karman Vortex Streets
The wake of a cylinder is a series of alternating vortices shed as the flow moves past. This distinctive pattern is known as a von Karman vortex street. The speed of the flow and the size of the cylinder determine how often vortices are shed. Incredibly, this pattern appears at scales ranging from the laboratory…
Turbulence and Star Formation
Galaxy clusters are objects containing hundreds or thousands of galaxies immersed in hot gas. This gas glows brightly in X-ray, as seen in the Perseus (top) and Virgo (bottom) clusters above. Over time, the gas near the center of the clusters should cool, generating many new stars, but this is not what astronomers observe. New…
Iridescent Clouds
Look up at the clouds on the right day and you may catch a glimpse of a rainbow-like phenomenon known as cloud iridescence. These colors occur when sunlight is diffracted through small water droplets or ice crystals. For the effect to be apparent, the cloud must be optically thin, meaning that most of the rays…
The Hidden Complexities of the Simple Match
Striking a match and blowing it out seems rather simple to the naked eye. But with high-speed video and schlieren photography, the act takes on new complexity. Schlieren photography is an optical technique that is incredibly sensitive to changes in density, which makes it a prime choice for visualizing flows with temperatures variations or shock waves.…
FYFD at APS DFD 2014
I’m excited to announce that I will be attending the American Physical Society Division of Fluid Dynamics meeting in San Francisco next month. This year I will be co-teaching a workshop on communicating science to general audiences. Here’s the lowdown: Scientist-Reporter Workshop: How to tell your science story Want to share your research with the…
Momentary Crown
When a drop falls on a liquid film, its impact drives a thin liquid sheet called the ejecta upward and outward from the point of impact. Within milliseconds, tiny perturbations develop in the ejecta and begin growing exponentially. These become the distinctive spikes of the crown. The momentum from the impact drives the ejecta and…