An experimental study on the phenomenon of flow field around the limbs of cyclists

Abstract

Reduction of aerodynamic drag is an important topic in the development of a bicycle racing, making it extremely vital to study the flow field phenomenon on the surface of a cyclist. As the wind flows over the human body, the flow separation phenomenon will appear on the surface. The purpose of this research is to study the aerodynamic characteristics of cyclists by utilizing flow visualization method in both water channel and wind tunnel. Cyclist models used in water channel and wind tunnel testing were based on a real male cyclist and printed using a 3D printer. Flow visualization technique was employed to observe the flow phenomenon around the arms, thighs and calves of the cyclist model. It is found that there are vortices meandering along the axial direction at the arms and thighs, double separation lines appear at the lower legs. Then, the surface pressure coefficient of the model was measured on a full-scale model in wind tunnel experiment to verify the flow condition in the vicinity of the model surface. These research methods help in getting a better understanding of the structure of the flow field around the cyclist, and further achieve the purpose of drag reduction.

Keywords

• cyclist
• axial vortex
• aerodynamic
• flow visualization
• flow separation