To better understand how to optimize the flow of water around a swimmer and create the designs and materials to give competitive athletes a winning edge, Speedo, the world's leading swim brand, is designing the next generation of their FASTSKIN performance swimwear using Silicon Graphics technology. Performance-intensive computational fluid dynamics (CFD) analysis based on data of Olympic swimmers -- monitored in Speedo's Aqualab research and development facility -- is run on an SGI Altix high-performance computing system. According to Speedo, the company was the first swimwear company to use CFD analysis to design swimwear and athletic wear. Rerunning CFD models of previous FASTSKIN designs in order to create newer, even more hydrodynamic models that will further reduce high skin-friction drag, Speedo gets much faster results over commodity PC clusters by using the SGI Altix, which runs eight Intel Itanium 2 processors in a SGI shared-memory architecture Linux environment.

"I chose the SGI Altix for one reason: speed," said Barry Bixler, a key member of the Aqualab Research and Development Team. "CFD is one of the most time-consuming, intensive number-crunching activities that you can use a computer for, and I can use all of the eight processors running in parallel on the Altix. When I was using a PC cluster, some jobs would take almost a week to run. I can now run similar jobs on the Altix overnight -- start it off in the evening, wake up in the morning and it will be done. I get really good turnaround time and the fact that I can run a job overnight instead of having to wait a week, that's an incredible increase in my productivity."

Bixler, also an aerospace engineer, is now using the SGI Altix system to develop the next generation of FASTSKIN. Using the FLUENT CFD program, he is doing much more sophisticated analysis than ever before. "I have used the FLUENT program for several years now, and its stability and many features have allowed me to tackle a variety of fluid flow problems for Speedo. FLUENT runs extremely well on the SGI Altix, where all the time-critical number-crunching takes place, and when I get results, I just post-process them on my PC home computers," said Bixler. "We look at the speed and the direction of the flow, and where it leaves the body, and where it reattaches itself. And of course we're always interested to see where the skin friction drag is high, and where it is low."

Most competitive swimmers, male and female, wear some type of full body suit that either covers wrists to ankles, or sleeveless, with torso and legs covered; some prefer torso and a leg length to just above the knees. Speedo makes all the varieties and combinations, yet Bixler (and many others) believe athletes can swim faster in the longer suits because the suits streamline the body and channel the flow around the body, reducing drag. Amazing amounts of research go into the carefully designed fabrics and silhouettes of competitive swimwear. FASTSKIN material, for example, more closely resembles a shark's skin than human skin, down to the tiny riblets (ridges) on the surface.

CFD modeling shows how the water flows around the body. Different suits are designed for male and female athletes because CFD has determined there is a more separated flow, where the water actually leaves the surface of the swimmer, for females than males.

"The shared-memory architecture of the SGI Altix system, which speeds up the design process by shortening data access time and computational runs, is the perfect tool for complex CFD analysis, whether designing next-generation swimsuits, cars, airplanes or rockets," said Himanshu Misra, manager, engineering analysis segment, SGI. "As the growing numbers of SGI Altix HPC customers in all those fields know, speed of analysis is paramount in time to market and maintaining a competitive advantage."