Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Soap Film Wakes
Soap films can create remarkable flow visualizations when illuminated with monochromatic (single color) light. Each of the photos above shows a flow moving from left to right with a small object near the left creating an obstruction. In the top two images, the objects are cylinders; in the lower one it’s a flat plate tilted…
Rio 2016: Diving
Diving is a popular event for spectators, but it can also be rather confusing. We know that divers are rewarded for minimizing their splash, but what exactly does that mean and how do they do it? The ideal water entry, called a rip entry by divers, requires a diver to hit the water in a…
Rio 2016: The Swimming Pool Controversy
Statistical analysis suggests possible current in the Rio Olympics swimming pool Several news outlets, beginning with The Wall Street Journal, are reporting that the swimming pool in Rio may have had a current that biased athletes’ performances. This is based on a statistical analysis of athlete performances across the meet, conducted by Indiana University’s Joel…
Rio 2016: Badminton
Badminton is unusual among racquet sports because it does not use a sphere as its projectile. Instead players hit a shuttlecock, traditionally made from a cork ball and a skirt of goose feathers. Despite its unusual shape, the shuttlecock reaches some of the fastest speeds in sports – over 330 kph (200 mph)! The shuttlecock’s…
Rio 2016: Sailing and Rule 42
If you watch some of the sailing in Rio, you may hear commentators mention sailors being penalized for breaking Rule 42. Broadly speaking, Rule 42 says that sailors can’t use their body to propel the boat. While it seems like a little rocking couldn’t make much difference, it turns out events have these rules for…
Rio 2016: Long Jump
Long jump, like many track and field events, is affected by fluid dynamics in subtle ways. Both wind speed and altitude can modify a jumper’s performance – first, by changing the maximum speed they reach in their sprint, and second, through aerodynamic drag while in flight. Air resistance accounts for roughly 10% of a sprinter’s…
Rio 2016: Synchro Swimming and Water Polo
Both synchronized swimming and water polo require competitors to hold themselves stable above the water’s surface without touching the pool’s bottom. One of the basic techniques for doing so in both sports is known as the eggbeater kick, shown above. The eggbeater kick is very similar to the motion for the breaststroke’s kick, but it’s…
Rio 2016: Track Cycling
Track cycling is a sport where speed is everything. As much as 90% of the resistance a rider has to overcome is aerodynamic drag. To minimize drag, riders wear form-fitting one-piece skinsuits and wear special, streamlined helmets. They have aerodynamic bikes (unique left-side-drive ones, if you’re the Team USA women) and ride with their arms…
Rio 2016: Table Tennis
Many sports use spherical balls, but the small size and weight of a table tennis ball makes it the one where aerodynamics have the strongest effect. Spin also plays a big role in the game by creating asymmetry in the flow around the ball. Consider a table tennis ball with topspin, meaning that its upper…
Rio 2016: Whitewater Sports
The whitewater rapids of canoe slalom have their origins in mountain streams. Today the sport’s Olympic venues are artificial rivers, specially designed to provide world-class rapids whatever the geography of the host city. Rio’s course, like London’s, is reconfigurable; its features are controlled by the placement of Lego-like plastic blocks. A key part of the…