Everyone expects a good political demonstration or two at next month’s Olympic Games in Beijing. Maybe even a drug or doping scandal. There may also be complaints about the environment. And, you can count on some controversy surrounding all the advanced technology at the Games.
Yeah, technology.
Much of the attention—and tension—is expected to center on the “White Cube.” The drama in this spectacular swimming venue, which was designed and built for this year’s Olympics, will focus on the world’s top swimmers and their new Speedo LZR Racer swimsuits.
Speedo, the world’s largest swimsuit manufacturer, has adopted computational fluid dynamics (CFD) software to significantly reduce the drag and skin friction experienced by swimmers and compress their bodies into a more streamlined shape, enabling them to cut through the water with more power and agility (Fig. 1). CFD software is used in the aerospace and other industries as well as to simulate the performance of Formula One racecars and America’s Cup yachts.
Since the LZR Racer’s unveiling in February, swimmers wearing it have set a staggering 38 world records and renewed the debate over whether technology has too much influence over the sport (Fig. 2). Japanese swimmers set 17 new national records wearing the LZR suit in one weekend in mid-June.
“This is clear evidence of the power of applying advanced engineering simulation technology to optimize all of the design metrics of a product,” says Jim Cashman, president and CEO of Ansys Inc., which helped design the new suit. Alberto Castagnetti, Italy’s national swimming coach, though, compared wearing the new Speedo suit to “technological doping.”
Speedo had a lot of help designing the suit, primarily from Ansys, a simulation software specialist, and Aqualab, Speedo’s own in-house R&D group. But it also worked with researchers at the University of Otago in New Zealand, the University of Nottingham in the U.K., the Australian Institute of Sport, Optimal Solutions in the U.S., and NASA.
In a sport where hundredths of a second can mean a gold medal or no medal at all, the Speedo research team has cut the passive drag of the LZR Racer by 10% from the earlier Fastskin FSII model and by 38% over ordinary Lycra swimsuits still used by a few world-class swimmers.
GO WITH THE FLOW
Skin-drag is inherent in swimsuit fabrics, so work on the new suit, priced by Speedo at a hefty $290, started by identifying the most drag-resistant fabrics. Researchers also took body scans of over 400 elite swimmers to provide geometries for testing more than 100 different fabrics and suit designs.
To test the fabrics and create a suit with the least drag, they used water flumes at the University of Otago. NASA contributed by evaluating the surface friction of fabric candidates in its low-speed wind tunnel, operating at 28 meters per second to simulate swimmers moving at two meters per second in the water. NASA used an aluminum plate as a benchmark for the fabric tests.
Drag reductions identified in the water flume and wind tunnel translated to a 4% increase in speed for swimmers when wearing the new suit as opposed to wearing their regular training swimwear. The new suit even improved the swimmers’ oxygen utilization by 5% compared to the training wear.
Ansys focused its work on the passive drag of the suit design, which occurs when the body is in the glide position with arms outstretched in front and legs outstretched behind. Swimmers maintain this position for up to 15 meters immediately after diving and for a similar distance after kicking off underwater after each turn. CFD analysis by Ansys identified areas in which both skin-drag and form-drag occur.
The CFD simulations involved precise boundary-layer meshing techniques using software from Ansys and resolved fine fluid flow details using the precision-scanned geometries of elite swimmers. Armed with detailed fluid dynamics data from the CFD studies, Speedo and Ansys guided the final design of the new suit, such as the precise location of the ultra-low-drag LZR panels bonded onto the suit. The placement of the panels reduced skin-drag by 24% compared to Speedo’s Fastskin fabric suit.
Keith Hanna of Ansys, who lectures on the application of CFD technology in sports, says a big development could come from the use of comprehensive multiphysics technology for elite swimsuit design. That would mean using CFD with other physics, such as structural simulation, to simulate every aspect of real-world physics in a competitive scenario.
While Speedo and its worldclass swimming customers are raking in the gold, it’s not clear if Speedo has any competition. Japanese swimwear manufacturers launched an effort to prevent the country’s athletes from defecting to Speedo for the Beijing Games. In May, Mizuno, Descente, and Asics unveiled their own hastily designed hightech suits they hope will hold up competitively.
At the same time, privately held TYR Sport Inc., the second largest swimwear maker, filed suit against No. 1, the unit of the Warnaco Group that makes Speedo swimsuits. TYR alleges violations of federal and state antitrust laws, restraint of trade, and false advertising in connection with Speedo’s new suit.
TYR also sued USA Swimming, the sport’s national governing body, and its head coach, Mark Schubert, who allegedly told U.S. Olympic team hopefuls that they had better wear Speedo at this summer’s team trials for the Beijing Olympics “or they may end up at home watching on NBC.” The Japanese Swimming Federation resolved the issue for its swimmers in June when it said it would not require its athletes to wear the approved Mizuno, Descente, and Asics suits and that they could switch to the LZR suit.
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