Citation

Beaumont F, Taiar R, Polidori G, Trenchard H, Grappe F. J. Biomech. 2018; 67: 1-8.

Affiliation

EA 4660, laboratoire C3S, unité des sports (U-Sports), université de Franche-Comté, 25000 Besançon, France. Electronic address: frederic.grappe@univ-fcomte.fr.

Copyright

(Copyright © 2018, Elsevier Publishing)

DOI

10.1016/j.jbiomech.2017.10.042

PMID

29150346

Abstract

The aerodynamic drag of three different time-trial cycling helmets was analyzed numerically for 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 15 m/s without wind. The CFD simulations have focused on the aerodynamic drag effects in terms of wall shear stress maps and pressure coefficient distributions on the cyclist/helmet system. For a given head position, the helmet shape, by itself, obtained 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.

Copyright © 2017 Elsevier Ltd. All rights reserved.

Language: en

Keywords

Aerodynamic drag; Computational Fluid Dynamics (CFD); Time trial helmets