A Novel Approach for Skin Suit Aerodynamic Optimization Using Local Momentum Deficit

Abstract

Abstract:A new approach is introduced to evaluate the potential drag reduction by skin suit design in speed sport. The approach relies upon local flow information measured in the wake of a cyclist mannequin. Lagrangian Particle Tracking is employed to measure the distribution of time-average streamwise velocity in a cross-plane of 30 × 100 cm 2 behind the stretched leg of the rider at a range of Reynolds numbers (0.4 × 10 5 < Re < 2.4 × 10 5 ). The expected Reynolds number effect is observed: a general wake narrowing at increasing speed. Unexpected local effects are also identified, which may be due to local variations in geometry of the rider's leg. The conservation of momentum within a control volume containing the leg is used showing that the aerodynamic drag of the rider's leg can be decreased by application of surface roughness. This outcome is validated by repeated measurements using zigzag tape on the legs' surface.

Aerodynamic drag reduction in winter sports: The quest for “free speed”

“…These results indicate that rough textured fabrics should be restricted to the legs and lower arms, while smoother fabrics should be used on the remainder of the suit. Rather than using a pressure transducer to conduct a wake survey, Terra et al 92 used neutral density helium bubble flow visualization and Lagrangian particle tracking to measure the flow field behind the leg of a static cycling mannequin. This technique may have future application in selecting the optimal fabric for various limb segments in many sports.…”