Flow measurement gives Olympic swimmers the edge

In Sunday’s 400 Men’s Freestyle at the Olympics, the difference between first and third place was less than a second. One of the secret weapons of the US assault is a high-tech flow measurement technique at developed Rensselaer Polytechnic Institute in Troy, New York, which aims to help athletes gain a few extra milliseconds in the pool, and a few vital centimeters on the podium.

Professor Timothy Wei, head of Rensselaer’s Department of Mechanical, Aerospace, and Nuclear Engineering and acting Dean of the University’s School of Engineering, used sophisticated mathematics and stop-motion video technology to develop his flow measurement system in 2007. The technology uses force measurement tools, (originally developed for aerospace research), and the Digital Particle Image Velocimetry video-based flow measurement technique to pinpoint the movement of swimmers in real-time. The data allows trainers to analyze how much energy the swimmers exert and how their body affects the water.

“This is the real thing,” Wei said. “We have the physical system, we’re taking flow measurements of actual swimmers, and we’re getting more information than anyone has ever had before about swimming and how the swimmer interacts with the water. And so far, these techniques have contributed to some very significant improvements in the lap times of Olympic swimmers.”

“Swimming research has strived to understand water flow around a swimmer for decades because how a swimmer’s body moves the surrounding water is everything,” said USA Swimming’s Biomechanics Manager Russell Mark. “The ability to measure flow and forces in a natural and unimpeded environment hasn’t been available until recently, and Dr. Wei’s technology and methods presented USA Swimming with a unique opportunity that United States swimmers and coaches could learn a lot from.”

Dr. Wei’s flow measurement research also has applications in medicine – he has worked with a vascular surgeon to study effects of flow over endothelial cells, and partnered with a neurosurgeon to study the effects of excess fluid in the brain. Wei has also worked with marine biologists at the University of California, Santa Cruz, to study the flow of bottlenose dolphins.

Video of the system in action can be seen here.