Drag Kings: characterizing large-scale flows in cycling aerodynamics

In their recent publication Crouch et al. (J. Fluid Mech., this issue, vol. 748, 2014, pp. 5-35) use wind tunnel experiments to quantify the large-scale vortical structures that develop as a cyclist progresses through a full rotation of the pedals. The authors identify asymmetries in the trailing vortex wake, which intensify as one leg straightens, as the primary source of drag variation over one pedal cycle. These new data suggest that targeted approaches to mitigate asymmetries in the trailing wake present an intriguing opportunity to reduce drag in cycling strategies and technologies.