Numerical simulation of the aerodynamic effects of downforce-generating wings on trailing motorcycles: stability and safety considerations

Abstract This study investigates the aerodynamic influence of a wing-equipped motorcycle on a pursuing motorcycle under close-racing conditions. Numerical simulations using RANS with the k – $$\omega$$ SST model were carried out for several relative longitudinal and lateral positions. The results show that the aerodynamic wake of the leading motorcycle affects the trailing one through two independent mechanisms: the turbulent low-pressure wake, which facilitates drafting, and the coherent wingtip vortices, which generate upwash and reduce the drafting benefit. Depending on the relative positioning, these effects can either increase instability by amplifying lift and pitching moments, or reduce wheelie tendencies through beneficial downwash. Quantitative comparisons of drag, lift, and pitching moment coefficients demonstrate that aerodynamic loads from the leading motorcycle are of the same order as static weight-induced moments, highlighting their role in braking stability and control. The findings contribute to a better understanding of aerodynamic interactions in motorcycle racing and provide insights relevant to discussions on safety and regulation.