Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Crown Sealing
Objects falling into a liquid pool create a beautiful splash, and, in this beautiful, award-winning video, the Splash Lab explores a peculiar instability that occurs just as the splash closes. The buckling instability they describe involves distinctive ridges that form along the splash’s ejecta sheet as it domes over and closes. The number of ridges…
Beverage Bubbles Bursting
Fizzy drinks like soda and champagne have many bubbles which rise to the surface before bursting. When the film separating the bubble and the air drains and bursts, it leaves a millimeter-sized cavity that collapses on itself. That collapse creates an upward jet of fluid which can break into tiny aerosol droplets that disperse the…
Raindrops on Sand
Here is a high-speed look at the impact of a raindrop on a sandy beach. In this case, a water droplet is falling on a bed of uniform glass beads, but the situation is effectively the same. Depending on the speed of the drop at impact, many types of craters are possible. The higher the…
Sound Interactions
Sound waves often interact with many objects before we hear them. Understanding and controlling those interactions is a major part of acoustic engineering. The animations above show shock waves–sound–from a trumpet interacting with different objects. The sound is made visible using the schlieren optical technique, allowing us to observe the reflection, absorption, and transmission of…
Wave Clouds
Coming home from APS DFD, I looked out the window as we flew east over the last of the Rockies and caught these wave clouds. Air flowing west to east gets disturbed by the mountains, which creates internal waves in the atmosphere. Generally, these are invisible–though they can cause some of the turbulence you feel…
Supercooling Water
Supercooling is the process of lowering a fluid’s temperature below its freezing point without the fluid becoming solid. Though this may sound bizarre, it’s an effect you can recreate easily in your refrigerator, as detailed in the video above. Supercooling shows up in nature as well, particularly with water droplets at high altitudes. If a…
Van Gogh and Turbulence
Turbulence is one of the great unsolved mysteries of classical mechanics. Many physicists and engineers have spent their careers trying to further our understanding of the subject and find the mathematical pattern that underlies its complex motions. But understanding turbulence and representing it artistically may be two different things. This video discusses some neat research…
Piazza del Popolo
The lions of the fountain in Rome’s Piazza del Popolo eject a turbulent sheet of water. Random fluctuations in the water sheet cause holes to form. Driven by surface tension, these holes grow and merge, leaving behind ligaments of water which quickly break up into a spray of unevenly-sized drops. (Image credit: E. Villermaux)
Coalescence in Microgravity
Click through to see. Microgravity is a wonderful playground for fluid dynamics. Here astronaut Reid Wiseman demonstrates the interplay of forces involved in coalescence. When smaller droplets hit with insufficient force, they bounce off the water sphere. But if they hit hard enough to overcome surface tension, they coalesce with the sphere. I think the…
DFD Reminder
Reminder: APS DFD is starting today. Follow along on Twitter at @fyfluiddynamics and #APSDFD. Later today at 12:30 PT you can follow our science communication workshop and ask questions at #DFDSciComm.