Computational Fluid Dynamics (CFD) has found increasing use by aerodynamicists in recent years. Highly affordable computer hardware coupled with advances in computational techniques and availability of commercial CFD codes support this trend. However, as is true with any computer simulation, there is always a need for comparing aerodynamic CFD predictions extensively to the results measured in wind tunnel experiments.
One such calibration study has been initiated by Ford Motor Company to assess the predictive ability of commercially available CFD codes for the aerodynamic design of automobile shapes. Several codes have been checked against a set of detailed wind tunnel measurements on a number of car shapes. The work is being continued to date. This study has provided a significant information base for comparison of predicted and measured flow fields.
This report presents a limited mesh sensitivity analysis using a commercially available code, FIDAP, to predict the wind tunnel measurements of the C1 notchback car shape.
Results from three different discretizations are compared with the experiment. In general, the calculated and measured centerline pressure distributions on the front end and underbody compare well for all the meshes. The wake flow structure and floor pressure distributions show significant improvement for the denser mesh. The predicted drag coefficient is in good agreement with the measurement.