Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Jet-Based Control
Researchers have flown the first aircraft designed to maneuver without conventional control surfaces like ailerons and flaps. Instead of changing the wing geometry to alter the lift on different parts of the craft, the UAV uses strategically placed jets of air along the wing to control its flight. The plane can also alter the direction…
Steam Devils
The formation of the ethereal steam devil is quite similar to the formation of a fire tornado. In this case, the first frost of the season cooled air temperatures substantially below the temperature of the water of the lake, creating conditions for steam and for updrafts of rising, warmer air. A slight breeze across the…
Wind Turbines and Weather
A new study reports that wind turbine farms may be changing local surface temperatures, resulting in warmer temperatures at night and cooler temperatures during the day. The result is neither surprising nor new; the motion of the propellers increases the turbulence downstream of the turbines. Turbulent flow mixes much better than laminar flow, so air…
Jupiter and the Kelvin-Helmholtz Instability
Jupiter, known for its colorful bands of stormy clouds, is a beautiful subject for fluid dynamics in action. As the planet turns, the cloud bands move at different relative speeds. This velocity difference at the interface of the bands can trigger the Kelvin-Helmholtz instability, resulting in a line of whorls where the cloud bands meet.…
Non-Newtonian Fluids
[original media no longer available] Non-Newtonian fluids have even made it into pop culture. #
Wingtip Vortices in Ground Effect
In this flow visualization, wingtip vortices from an aircraft have been simulated using an apparatus with a couple of flaps that snap together like a book closing. Dye is pooled on the “ground” below the flaps and gets entrained by the vortices and lit up using laser light. The red vortices are the primary vortex…
Paper Plane Physics
[original media unavailable] It’s a little surprising that this would be so stable, but I don’t have any reason to believe it impossible. #
Wild Ferrofluid Shapes
In this fluid experiment, a ferrofluid–typically a liquid with a suspension of ferric particles–is exposed to rotating magnetic fields, which results in some wild shapes. #
Benard Cells
When a fluid in a gravitational field is heated from below, it can develop a Rayleigh-Benard instability which causes the formation of convection cells as in the video above. The hexagonal shape of the cells is due to the boundary conditions of the fluid. It’s possible to form other shapes like spirals. The same mechanism…
Human-Powered Ornithopter
A team at the University of Toronto has flown the world’s first human-powered ornithopter, an aircraft that flies by flapping its wings like a bird. The concept dates back all the way to Da Vinci in the 15th century. Part of why it’s taken centuries to realize the dream is that bird flight is much…