Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Brine Shrimp Swimming
For small creatures, swimming is dominated by viscosity. Here researchers use particle image velocimetry (PIV) to explore the flow field around brine shrimp. Its motion is divided into two vorticity-generating phases–the wide power stroke where the shrimp generates most of its forward motion and the recovery stroke where the shrimp returns its starting position while…
Granular Eruptions
Granular flows, which are made up of loose particles like sand, often display remarkably fluid-like behavior. Here researchers explore the behavior of granular flows when a solid impacts them at high speed. The sand, unlike a fluid, does not have surface tension, yet we still observe many of the same behaviors. Like a fluid, the sand…
Tornadogenesis
Tornadogenesis–the formation of tornadoes–remains a topic of active research as there is relatively little direct experimental data, owing to the difficulty of prediction as well as measurement. Initially, a variation of wind speed at different altitudes in the atmosphere causes shearing, which can lead to the formation of a horizontal column of rotating air–a vortex…
Plumes Driven by Chemistry
This timelapse video shows the formation and steady-state behavior of a buoyancy-driven plume created by a chemical reaction. As the plume accelerates upward, it develops a head, which in some cases detaches from the plume in the form of a vortex ring. A new head then develops before also detaching and accelerating upwards. (Video credit:…
Squeezing Bubbles
An air bubble trapped inside a viscoelastic fluid is squeezed between two plates in this video, revealing a Saffman-Taylor-like fingering instability stemming from local stress concentrations. (Video credit: Baudouin Saintyves)
Winds Across the US
A collaborative project on data visualization brings to life the wind velocity data across the United States. The Wind Map is an interactive, nearly real-time indicator of wind conditions across the country, compiled on an hourly basis from the National Digital Forecast Database. Be sure to click through to see the data in motion. Observing the…
Micro Air Vehicle Flow Viz
A smoke wire shows the deformation of streamlines around a swept-winged micro air vehicle (MAV). These crafts typically feature wingspans smaller than one foot and, thus, never develop the type of flow fields associated with larger fixed-wing airplanes. This complicates theoretical predictions of lift and drag for MAVs as well as making them difficult to…
Visualizing Ocean Currents
Researchers used computational models of ocean currents to produce this video visualizing worldwide ocean surface currents from June 2005 through December 2007. Dark patterns under the ocean are representative of ocean depths and have been exaggerated to 40x; land topography is exaggerated to 20x. Notice the wide variety of behaviors exhibited in the simulation: some…
Vortex Cannon
Building a vortex cannon is a great way to demonstrate the power and longevity of vortex rings. As demonstrated here, it’s possible to create one with just a box with a round hole in it. Adding some smoke or stage fog helps visualize the rings. Vortex rings are found frequently in nature: volcanoes make them,…
Science Off the Sphere: Liquid Lenses
Astronaut Don Pettit delivers more “Science Off The Sphere” in his latest video. Here he demonstrates diffusion and convection in a two-dimensional water film in microgravity. He notes that the viscous damping in the water is relatively low and that, left undisturbed, mixing in the film will continue for 5-10 minutes before coming to rest, which…