Correction of Wind Tunnel Data: a Numerical Analysis of the Different Contributions

The experimental data corrections on automotive wind tunnel test usually take profit by the pre-test corrections methodology, which is able to breaking down the working time. This methodology is based on the use of CFD simulations and carries out a global correction factor. It is interest to analyze the different contributions to the correction (wind tunnel walls effects, supports, Reynolds number) and their eventual dependence by the involved parameters. Therefore, in the present paper, the main purpose is to describe, with the support of a CFD analysys, the influence of the main factors that contribute to the final correction factor. A high performances car was taken as reference model and the RANS equations were used as fluid dynamic model. In a preliminary part the CFD methodology and its validation, through a comparison with experimental data, are presented. The different contribution to the correction terms are presented and discussed. Finally, for each of these factors, the contribution of the different parts of the car is evaluated. The car was splitted in body, wheels, underbody, radiators, internal ducts and volumes and rear wing