Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Shark Wakes
Volumetric imaging of swimming spiny dogfish, a type of shark, shows that their distinctively asymmetric tails produce a set of dual-linked vortex rings with every half beat of their tail. The figure above shows data from the actual shark on the right (b,d,f) and a similarly shaped robotic tail on the left (a,c,e). The second row…
Freezing Drops
[original media no longer available] The physics of droplets freezing is important for understanding applications like ice formation on airplane wings. Here we see how a warm droplet deposited on a cold plate freezes. A freezing front advances through the drop, which expands vertically as it freezes. Ultimately, the expansion of the ice and the…
Stone-Skipping Physics
Many people have learned to throw skipping stones across a pond or lake, but how many have considered the physics of how it happens? In this video, researchers use high-speed video to explore the skipping of various balls across water. The deformation of the ball as well as the shape of the cavity its impact…
High-Speed Droplet Collisions
This high-speed video shows the apparatus often used by photographers for fluid sculptures created from droplet collisions. As amazing as these formations are in still images, seeing their evolution at 5,000 fps is even more lovely.
Pitching Plate Flow Viz
This photograph uses fluorescent dye to visualize the wake behind a rigid flat plate pitching about its leading edge. A vortex is shed from the plate twice in each cycle of oscillation. These vortices entangle, producing the structured wake above. The top photo shows a side view of the wake, the bottom photo is a top view.…
Sewer Combustion
Enjoy a little high-speed video of combustion (the safe way!) this Thanksgiving holiday. For non-U.S. folks, have a great Thursday!
Superfluid Fountains
Superfluids, a special type of fluid located below the lambda point near absolute zero, exhibit some mind-bending properties like zero viscosity and zero entropy. They are, in essence, a macroscopic manifestation of quantum mechanics. Here their thermomechanical, or fountain, effect is explained. This bizarre state of matter isn’t only found in laboratories, though. Scientists now…
Sloshing Dynamics
[original media no longer available] Sloshing refers to the motion of a liquid inside a moving container, for example, in tanker trucks or inside a spacecraft’s fuel tank. The motion of the liquid payload can drastically affect the dynamics of the vehicle carrying it due to the ever shifting center of mass. In the video…
Faces from Laminar Mixing
These images show the laminar mixing that occurs when a flat plate moves up and down in an otherwise motionless fluid. Each face-like snapshot represents a different point in time. The longer the plate oscillates, the more elaborate the “faces” become. (Photo credit: S. Brunton)
Wingtip Vortices in Ground Effect
[original media no longer available] If you’ve ever watched airplane contrails fade, you’ve probably observed the Crow instability, which causes the trailing wingtip vortices of the plane to interact and distort. The same effect is explored in the video above with the addition of ground effect. The first clip shows a pair of counter-rotating vortices…