Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Propagating Flames
Like many flows, flames can be unstable and undergo a transition from orderly laminar flow to chaotic turbulent flow. The timelapse image above shows the propagation of a flame front travelling downward. Each blue line represents the forwardmost position of the flame at a specific time. The flame is essentially two-dimensional, held between two glass…
Stepping on Lava
What happens when you step on lava? (First off, don’t try this yourself.) Lava is both very dense and very viscous, so, as illustrated in the animation above, it does not give all that much under pressure. If you were to fall on it, you’d land, sink a little bit, and then get burned. It’s…
Simplified Schlieren Set-up
Schlieren photography offers a glimpse into flows that are usually invisible to the human eye. With a relatively simple set-up–a light source, collimating mirror(s), and a razor blade–it becomes possible to see differences in density. The technique lets one visualize temperature-driven flows like the buoyant convection from a flame or other heat source, and it…
Foggy Canyon
Timelapse photography reveals the tide-like motions of fog that filled the Grand Canyon last week. This unusual meteorological condition was created by a temperature inversion. Usually air near the ground is warmest and the atmosphere cools as the altitude increases. But occasionally a mass of warm air will trap a layer of cooler air beneath…
Jumping Droplets
When droplets on a superhydrophobic surface coalesce with one another, they jump. Individually, each drop has a surface energy that depends on its size. When two smaller droplets coalesce into a larger drop, the final drop’s surface energy is smaller than the sum of the parent droplets. Energy has to be conserved, though, so that excess surface energy…
Phytoplankton Flow Viz
Nutrient-rich waters off Patagonia in South America blossom with phytoplankton in this satellite image. When present in large quantities, these microscopic photosynthesizers lend a green hue to the water. They act as seed particles in the flow, highlighting the currents and flow that carry them. If you check out the full resolution version of the…
Frog Tongues and Parrot Laser Safety Goggles
What do frog tongues, whisky, tattoos, and parrot laser safety goggles have in common? They’re all a part of the latest FYFD video! Check out my behind-the-scenes look at the biggest fluid dynamics conference of the year and find out what science everyone was talking about. (Image credits: N. Sharp, source video)
Behind the Science
FYFD features lots of science, but this new video gives you a chance to see the scientists, too! It’s a behind-the-scenes look at the American Physical Society Division of Fluid Dynamics meeting that took place in San Francisco recently. You may recognize some of the stories, but I guarantee there’s new stuff, even if you…
Half Vortex Rings
Vortices are one of the most common structures in fluid dynamics. In this video, Dianna from Physics Girl explores an unusual variety of vortex you can create in a pool. Dragging a plate through the water at the surface creates a half vortex ring, which can be tracked either by the surface depressions created or…
Vertical-Axis Wind Turbines
Vertical-axis wind turbines (VAWT) are an alternative to traditional wind turbine designs. Unlike their more common cousins, VAWTs rotate about a vertical axis and are omni-directional, meaning that they do not have to be pointed into the wind to produce power. While their size allows VAWTs to be packed much closer to one another than traditional…