Andrea Sciacchitano, assistant professor in aerospace at TU Delft, told Reuters that aerodynamics is crucial to time trial performance.
"In order to go faster aerodynamics is very important, it's up to 90 percent of the total resistance that the guy has to overcome - and the roughness of the fabric is very important in order to reduce drag," he said. "One may think that in order to go faster the surface must be very smooth. This is, in fact, not always the case. In some cases some roughness can help the guy to go faster because it energizes the flow close to the surface. So it allows the flow to close on the back and therefore to reduce the aerodynamic drag."
Sciacchitano said a technique developed at the university called particle image velocimetry (PIV) proved crucial in the wind tunnel tests. Helium-filled soap bubbles were used to map the flow and ensure good measurements.
"In the wind tunnel we can have a very controlled environment, very specific flow velocity. Particle Image Velocimetry, is a particular technique that we have developed at TU Delft, in which we introduce small particles in the flow, we illuminate them by means of a laser and we take images of these particles - and by measuring the displacement of these particles at two time instance we can determine the velocity field and therefore the pressure and finally the aerodynamic drag," he said.
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