Aerodynamic analysis of different cyclist hill descent positions

• Published in: Journal of wind engineering and industrial aerodynamics Vol. 181; pp. 27 - 45
• Main Authors: Blocken, Bert, van Druenen, Thijs, Toparlar, Yasin, Andrianne, Thomas
• Format: Journal Article Web Resource
• Language: English
• Published: Elsevier Ltd 01.10.2018; Elsevier
• Subjects: Aerodynamic cyclist drag; Aerodynamics; Aerospace & aeronautics engineering; Computational Fluid Dynamics; Cycling aerodynamics; Cycling position; Drag; Engineering, computing & technology; Ingénierie aérospatiale; Ingénierie mécanique; Ingénierie, informatique & technologie; Mechanical engineering; Numerical simulation; Physical, chemical, mathematical & earth Sciences; Physics; Physique; Physique, chimie, mathématiques & sciences de la terre; Wind Tunnel; Numerical simulation; Cycling position; Wind tunnel; Cycling aerodynamics; Computational fluid dynamics; Aerodynamic cyclist drag
• ISSN: 0167-6105; 1872-8197; 1872-8197
• DOI: 10.1016/j.jweia.2018.08.010

Different professional cyclists use very different hill descent positions, which indicates that prior to the present study, there was no consensus on which position is really superior, and that most cyclists did not test different positions, for example in wind tunnels, to find which position would give them the largest advantage. This paper presents an aerodynamic analysis of 15 different hill descent positions. It is assumed that the hill slope is steep enough so pedaling is not required to gain speed and that the descent does not include sharp bends necessitating changes in position. The analysis is performed by Computational Fluid Dynamics (CFD) simulations with the 3D RANS equations and the Transition SST k-ω model. The simulations are validated wind tunnel measurements. The results are analyzed in terms of frontal area, drag area and surface pressure coefficient. It is shown that the infamous “Froome” position during the Peyresourde descent of Stage 8 of the 2016 Tour de France is not aerodynamically superior to several other positions. Other positions are up to 7.2% faster and also safer because they provide more equal distribution of body weight over both wheels. Also several positions that allow larger power generation are aerodynamically superior. [Display omitted] •No consensus in pro cycling on which hill descent position is aerodynamically superior.•We analyze 15 different hill descent positions by numerical simulation with CFD.•CFD simulations are validated with wind tunnel measurements.•Ranking of 15 positions in terms of aerodynamic performance.•Infamous Peyresourde Froome position is not aerodynamically superior.