The Role of CFD on the Aerodynamic Investigation of Motorcycles 2003-01-0997
The aerodynamic evaluation that influences the shape of new vehicles is only one of the many different aspects that must be carefully considered in a vehicle design program. However, the aerodynamic development enters from the earliest stages, in the shape optimization program, and continues up to full production level, until the detail is optimized. As wind tunnel measurements continue to be the most common and extensively used approach, the rapid evolution of computers in terms of electronic data processing and storage and the progress achieved in computational fluid dynamics (CFD), suggest its utilization in supporting and reducing experimental tests. Multiple reasons can be given for that:
it is too expensive, especially for motorcycle industries, to use and/or construct a wind tunnel facility;
numerical results could be cheaper and quicker to obtain;
the flow around the vehicle can be predicted by numerical means;
wind tunnel results must be extended to “real life” and this could be done by means of numerical simulations after a proper validation of the code.
The aim of this paper is to examine the use of computational fluid dynamics as a tool for motorcycle aerodynamics investigation. The aerodynamic performance of a maxiscooter is predicted by means of a CFD software package. that solves indirectly the equations for the continuum (Navier-Stokes) by reproducing the fluid dynamics at the molecular level.
The critical element of motorcycle aerodynamics, compared to automobile aerodynamics, is that the pilot contributes to the frontal surface of the vehicle. Therefore, the potential influence of the rider and of the pillion passenger are investigated.
Moreover, as an example of geometry optimization, the effect of the windshield and of its angle of attack on the aerodynamic performance of the vehicle have been studied.