The aerodynamic drag of three different time-trial cycling helmets is analyzed numerically from two different cyclist head positions. Computational Fluid Dynamics (CFD) methods were used to investigate the detailed airflow patterns around the cyclist for a constant velocity of 15m/s without wind. CFD simulations were used to study the aerodynamic drag of the cyclist/helmet system which is closely related to the distribution of shear and pressure coefficients. We show that for a given head position, the helmet shape, by itself, has a weak effect on a cyclist’s aerodynamic performance (<1.5%). However, by varying head position, a cyclist significantly influences aerodynamic performance, the maximum difference between both positions being about 6.4%. CFD results have also shown that both helmet shape and head position significantly influence drag forces, pressure and wall shear stress distributions on the whole cyclist’s body due to the change in the near-wake behavior and in location of corresponding separation and attachment areas around the cyclist
Computational Fluid Dynamics (CFD), time trial helmets, aerodynamic drag
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