Virtual prototyping brings hi-tech into the swim

09 July 2012

Competitive swimmers this summer can streamline their performance thanks to Speedo's revolutionary Fastskin Racing System, which received full FINA (Fédération Internationale de Natation) approval last year. Les Hunt discovers how engineering simulation software from Ansys proved the Fastskin system design while reducing dependence on costly real-world testing.

"Engineering simulation has been absolutely critical in launching this world-first concept," says Tom Waller, who heads up Speedo's in-house global research and development facility, Aqualab. "For the first time, competitive swimmers can use a cohesive, hydrodynamic solution that will help them cut through the water with maximum efficiency.”

Aqualab used data from more than 1,200 separate simulations conducted with Ansys multi-physics software. By replicating the dynamic pressures of competitive swimming in a risk-free virtual design environment, these simulations helped engineers to minimise the effects of turbulence and drag, mitigate the impact force generated by a dive, maximise the structural strength of the goggle assembly, and address other real-world design concerns.

Following the design work, Speedo conducted a number of pool tests of the new racing system, using professional athletes, among them Natalie Coughlin, Ryan Lochte and Michael Phelps of the United States. Tom Waller again:

“In developing the Fastskin Racing System, Ansys software gave us the confidence that our designs would perform as expected in the real world, and saved us a huge amount of resources that we would otherwise have had to invest in physical testing."

While Speedo is a long-time Ansys customer, development of the new racing system relied on an expanded, multi-physics perspective that included both fluid dynamics and structural mechanical analyses, the latter being of particular relevance to the design of the goggles. For these, Ansys offered insight about the structural forces that impact the equipment from all directions, which lightweight material would be able to withstand those forces, and how the shape generated turbulence might impact negatively upon the swimmer's downstream performance.

While the physics pertaining to the performance of a swimmer at the peak of his or her game are complex to say the least, there are several key factors that had to be taken into account during this design exercise. Passive drag affects the swimmer during the submerged, glide phase of any stroke, which is particularly important after the start and at each turn. Oxygen economy relates to the swimmer's efficiency and his consumption of oxygen during the activity. Active drag (or surface drag) affects the swimmer at the surface during the active swimming phase of any stroke. It results from the waves that the swimmer creates, the swimmer's constantly changing shape and the force of the water passing over the body's surface.

The Fastskin Racing System comprises a choice of products, including caps, goggles and suits, allowing swimmers to select the best combination to meet their preferences and performance needs. Research outcome statistics were compiled based on a combination of Speedo's Fastskin3 cap, Super Elite goggle and Super Elite swimsuit racing system components. These indicated that a full-body passive drag reduction of up to 16.6 percent was possible, as well as an 11 percent improvement in the swimmer's oxygen economy and a 5.2 percent reduction in body active drag when these parameters were compared with those of the same male athlete wearing a flat silicone cap, Speedo Aquasocket goggle and standard suit.