Aerodynamic Study of MotoGP Motorcycle Flow Redirectors

In recent years, the introduction of aerodynamic appendages and the study of their aerodynamic performance in MotoGP motorcycles has increased exponentially. It was in 2016, with the introduction of the single electronic control unit, that the search began for alternative methods to generate downforce that were not solely reliant on the motorcycle's electronics. Since then, all types of spoilers, fins and wings have been observed on the fairings of MotoGP motorcycles. The latest breakthrough has been Ducati's implementation of flow redirectors at the front and bottom of the fairing. The aim of the present study was to test two hypotheses regarding the performance of the flow redirector by responding to the corresponding research questions on its aerodynamic function and advantage, both in the straight and leaning position. In a preanalytical cognitive act, a visual study of MotoGP motorcycles was conducted and, accordingly, a 3D-CAD model was designed ad hoc in compliance with the FIM 2022 regulations for both the motorcycle and flow redirector. Numerical simulations using OpenFOAM software were then carried out for the aerodynamic analysis. Finally, the Taguchi methodology was applied as an effective simulation-based strategy to narrow down the combinations of geometric parameters, reduce the solution space, optimize the number of simulations, and statistically analyse the results. The aerodynamic performance of the flow redirector is highly dependent on the inlet flow when the motorcycle is in a straight position. The results indicate that all models with leaned motorcycle bearing the flow redirector, regardless of geometry, have an aerodynamic advantage, as the appendage generates downforce with a minimal increment of the drag coefficient. In a cornering situation, the flow separator in the flow redirector reduces the disadvantageous influence of wheel rotation on the "diffuser effect" by drawing the flow towards the outside of the curve, creating extra downforce.