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UB researchers help give swimmers an edge
By LOIS BAKER
Contributing Editor
The difference between finishing first and coming in second in competitive swimming is measured in milliseconds, so when a swimmer's technique and fitness is as good as it gets, a coach turns to one remaining variable to sharpen the competitive edge—the swimsuit.
Turbulators incorporated into the design decrease drag.
In that scenario, scientists in UB's Center for Research and Education in Special Environments may be a coach's best friends. They have a patent pending on a structural element that can improve a swimmer's time by decreasing the force water exerts on swimmers, called "drag," by 10 percent when incorporated into the swimsuit design.
The new element, which the researchers call a turbulator, alters the fluid dynamics of water as it flows over and around the swimmer. How drag acts on a body moving through water plays an important role in the amount of energy a competitor must exert to cover a specific distance: less drag, less energy required, quicker finish.
Trials of suits incorporating the turbulator into their fabric, conducted at UB over two years, showed that adding the element could improve a swimmer's time by 3 percent, said David Pendergast, professor of physiology and biophysics. Pendergast and Joseph Mollendorf, professor of mechanical and aerospace engineering, were senior researchers on the project.
TYR, the company that has licensed the technology and named it "Aqua Shift™," will introduce its new line of competition suits incorporating turbulators to the swimming world tomorrow at the FINA World Cup Swimming meet. The competition is being held at the Nassau Aquatics Center on Long Island.
The team of UB inventors who developed the technology will be at the launch of the new suit to discuss the underlying science and the performance trials conducted in the UB center's facilities.
The turbulator's science is grounded in the research team's earlier work in fluid dynamics and its success in decomposing drag, breaking it into its component forces. "No one else had done that before," Pendergast said.
"We discovered there are three types of drag. Friction drag, the force of water molecules as they pass over the body, is dependent on how long the body is. Pressure drag, the strongest force, results from pushing the water out of the way. Wave drag occurs at relatively high speeds and is the force exerted by waves created."
When the researchers separated drag into its three components, they found that pressure and friction drag exerted the highest influences, said Pendergast. Their next question was: How can drag be reduced?
Their first inclination was to change the surface of the swimsuit fabric, but that approach didn't reduce drag significantly. Enter the turbulator, a strategically placed, fabric-encased, flexible tube that introduces a raised ridge on the suit. Pendergast describes how this element improves the fluid dynamics of a swimmer.
"When water hits the shoulders of a swimmer, it separates from the body, which creates drag. By adding a turbulator, we cause water to follow the body instead of separating from it. This change increases friction drag, but reduces pressure drag. We found that placing a turbulator on the front and back of a suit significantly reduced pressure drag, overcoming the increased friction drag and adding a competitive advantage"
Meanwhile, TYR had approached Albert (Budd) Termin, II, UB's swimming coach, whose swimmers compete in the company's suits, about working on reducing drag. Termin has collaborated extensively with Pendergast and Mollendorf on improving swimming efficiency.
Over a two-year period, the team tested 20 suit models incorporating the turbulator for TYR at the Center for Research and Education in Special Environments. The trials took place in the center's special annular (doughnut-shaped) pool designed for conducting a variety of specialized research, including measuring drag and other hydrodynamic properties, and in UB's competition pool.
"The work was part theory and part practice," said Pendergast. "It turned out the size of the turbulator was crucial. We'd predict how a certain size and placement would respond, TYR would build the suit, and we tested and retested."
The final design incorporates a series of turbulators positioned on the suit front, across the shoulders and across the hips. UB research on suit design had shown that suits that cover the swimmer from shoulder to knee or ankle produce less drag than suits with less coverage.
Yana Klochkova, who won two gold medals for Ukraine in the 2000 Olympics and is sponsored by TYR, will model the new suit at tomorrow's unveiling.