The role and validation of CFD applied to cycling

The importance of drag reduction in elite cycling has been recognised by cyclists and engineers for many years. Aerodynamics has such an influential role that it is often the difference between winning and losing. In pursuit of minimising drag, computational fluid dynamics (CFD) provides an extremely powerful tool for investigating cycling aerodynamics. In the Sports Engineering Research Group at The University of Sheffield CFD is often used for this purpose. To develop confidence in the CFD results it is necessary to carry out validations; one such validation is presented in this paper. The flow around a front wheel and fork were analysed both in a wind tunnel and using CFD. The k-w turbulence model was found to give a slight over-prediction of drag wheel and fork. In comparison, all the other turbulence models consistently under-predicted drag by significant margin. From these results it appears the k-w model is the most suited to cycling aerodynamics. However, it is necessary to continue computational and experimental comparisons before firm conclusions can be drawn about the optimum CFD model for cycling.