New Delhi, Aug. 9: You have heard of mental math. How about water mathematics?

American swimmers at the Beijing Olympics may be armed with a secret recipe for success from an unlikely coach — Timothy Wei, a fluid mechanics professor at a top US engineering school.

Wei, head of the mechanical, aerospace and nuclear engineering department at the Rensselaer Polytechnic Institute in Troy (New York), has tailored experimental flow-measurement techniques to help swimmers improve their performance.

He has developed a method to analyse the flow of water around swimmers by combining mathematical tools originally developed for aerospace research with a technique called digital particle image velocimetry.

“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,” Wei, who designed the flow-measurement tool last year, said. “These techniques have contributed to some very significant improvements in the lap times of Olympic swimmers.”

The system uses sophisticated mathematics with video technology to identify key vortices, pinpoint the movement of water and find out how much energy a swimmer exerts with each movement of arm or leg.

The trick lies in deciphering how water moves around the swimmer. “You have to know the flow. You need to know how much force the swimmer is producing, and how that force impacts the water,” he said.

Most of the early tests with the flow-measurement system were conducted last October and coaches and swimmers have spent several months incorporating lessons from the findings into their style.

“The knowledge gained gave me the foundation for which every technical stroke change in preparation for the Beijing Olympics was based,” a press release from the Rensselaer Polytechnic quoted Sean Hutchison, the coach of the American team, as saying.

Wei worked with coaches, providing information on how swimmers could optimise their moves in water. The coach translated this advice into tips to help a swimmer improve performance, a Rensselaer source said.

Rensselaer is widely known to Indian science students as the institution of David Halliday and Robert Resnick, authors of a world-famous undergraduate physics textbook often prescribed to IIT aspirants.

“It takes time for a swimmer to make adjustments to their strokes and practise the new techniques,” said Wei, who started his career as an aeronautical engineer doing research for the US Navy. But he has recently moved into other areas — studying the mechanics of blood flow through blood vessels and the mechanisms of excess fluid build-up in the brain.

In the past, swimming coaches have often used computer simulation to try and improve performance, but the level of information available through the technology that Wei has developed surpasses anything else available.