Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Vertical Axis Wind Turbines
Conventional wind turbines feature horizontal axis propellers which must be placed far apart from one another to avoid wake interference. Researchers have found that using vertical axis wind turbines specially arranged to utilize the wake of one turbine to improve the efficiency of its neighbor can produce far more energy per square meter of land.…
Osborne Reynolds and Transition
How and when flow through a pipe becomes turbulent has been a conundrum for fluid mechanicians since the days of Osbourne Reynolds (~1870s): Typically, the laminar-to-turbulence transition is studied mathematically by linearizing the Navier-Stokes equations, the governing equations of fluid dynamics, then perturbing the system. These perturbations will gradually disappear in laminar flow, but if…
Aurora Physics
The auroras at Earth’s poles are much more than pretty lights. This video explains their formation; fluid mechanics (specifically magnetohydrodynamics) play a major role in the convective transport of heat inside the sun as well as the movement of the plasma that makes up a solar storm that interacts with Earth’s magnetic field and produces…
The Tibetan Singing Bowl
The vibration caused by rubbing a Tibetan singing bowl excites standing waves in a Faraday instability on the surface of water in the bowl. As the amplitude of excitation increases, jets roil across the surface, creating a spray of droplets, some of which actually bounce on the surface as it vibrates. For more see the…
Tour de France Physics: Wind Tunnel Testing
Over hours of racing, even a few grams of drag can be the difference between the top of the podium and missing out. For manufacturers as well as for individual professional cyclists, hours of wind tunnel testing help determine optimum configurations of equipment and positioning. During a day of wind tunnel testing, a cyclist…
Tour de France Physics: Time Trials
Unlike road stages in which cyclists can draft off one another to reduce drag, in the time trial a cyclist is on a solo race against the clock with nowhere to hide. As a result, the event features lots of technologies designed to reduce both pressure drag and skin friction on the cyclist. For time…
Drafting Behind a Big Rig
For those who like the effects of drafting in cycling backed up by Mythbusters, here’s a comparison between riding a mountain bike at 20 mph solo and on the tail end of a semi. #
Tour de France Physics: Lead-Out Trains
[original media no longer available] One of the most impressive cycling techniques for drag reduction on a rider is the lead-out train that delivers a sprinter to the finish line. No current team is better at this than HTC-Highroad. Watch for them in the white and yellow from about ~4:00 in the above video. The…
Tour de France Physics: Breakaways
In cycling, a small group of riders often leave the protection of the peloton in a breakaway. These riders will often spend 80% or more of a stage or race outside of the peloton, trying to reach the finish line before they’re caught. Because the pressure drag is so draining on a lone cyclist, it’s…
Tour de France Physics: Pelotons
July is well underway and for cycling fans around the world that means it’s time for the Tour de France. This week at FYFD we’re going to do something a little different: in honor of cycling’s biggest race, every post this week will focus on some of the fluid dynamics involved in the sport. On…