Cyclist Tom Dumoulin should tomorrow in the first time trial of the Tour de France five to ten seconds of time go packs with a new aerodynamic suit. That time profit is partly due to weeks of wind tunnel testing with a 3D-printed mannequin that exactly the size and posture of the rider. “The air resistance is so with 0.5 to 1%” says Dr. Daan Bregman.
For the new ribbelpak, developed by the Delft University of technology and Team Giant-Alpecin Dumoulin did not need one to pass through.
Based on this scan is a 3D-printed pop manufactured, which during wind tunnel experiments wore suits and different kinds of materials. The mannequin consists of eight parts, via pen-hole connections linked to simulate realistic attitudes.
The method is useful for two reasons, says Bregman. “You can a cyclist not weeks long each day in a wind tunnel. In addition, there is a mannequin perfectly silent, allowing the measurements of the air flows around the body more accurate and faster.”
Smooth and rough patches
The suit by Dumoulin is a combination of smooth and rough patches, which should keep the air longer contact with his body. This reduces the wake behind his body and thus the air resistance. The optimal pattern of rough and smooth patches depends on the shape and posture of the body. For the measurements using an innovative technique (Particle Image Velocimetry, see this YouTube video) to SOAP bubbles filled with helium to the air flow and with a laser.
The 3D-pop goes the wind tunnel in again soon for new tests. Bregman: “for example, an important question is: what kind of suit should Dumoulin to when it rains?” (Jeroen Akkermans)