Numerical simulations of the aerodynamics of a speedway motorcycle

This study presents a computational and experimental aerodynamic analysis of a speedway motorcycle, focusing on drag reduction strategies to enhance performance. Using Computational Fluid Dynamics (CFD) simulations in simcenter STAR-CCM+ and wind tunnel experiments, the aerodynamic characteristics of the motorcycle and rider are investigated. Wind tunnel experiments were conducted to validate the CFD methodology, showing a deviation of \(1.87\,%\) and \(-0.25\,%\) in drag area at \(30\,m/s\) and \(40\,m/s\) , respectively, confirming the reliability of the numerical model. The rider is identified as the primary drag contributor, accounting for over 50 % of the total aerodynamic resistance, with significant contributions from the front fairing and exposed limbs. A comparative study of stationary and rotating wheels reveals that wheel rotation increases drag by 1.61 %, primarily due to the turbulent flow structures they generate. Based on the findings, the front end of the motorcycle is redesigned and a new hand cover design is proposed, achieving a 9.1 % reduction in total drag by minimising high-pressure zones and wake turbulence. These results demonstrate the potential for aerodynamic improvements in speedway racing motorcycles, providing a foundation for future research on rider posture optimisation and advanced fairing designs.