Missing Michael Phelps' Chest

My interest in the swimming contest at the Olympics just plummeted with the news that old-style speedoes will be missing this year. (Michael Phelps' hot new mustache might bring me back, though.) Those modesty-protecting all-body outfits (developed by Speedo) are nonetheless a wonder of technological innovation and research:

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.

( Photo: Nick Laham/Getty).