Computational fluid dynamics simulation of the exterior flow field around an aerodynamic reference model

The exterior flow field around a Ford notchback automobile aerodynamic reference model was investigated using a commercial Computational Fluid Dynamics (CFD) code, Ansys Fluent. Two computational domains were set up in order to represent different model mounting conditions. According to the comparisons, good simulation accuracy could be obtained using the steady state k-omega SST model with small size near wall mesh (y(+)<5) simulations. The comparatively large prediction errors Of the surface pressure coefficient of the model centerline happened in two positions. One is the roof trailing edge, where the flow separation begins. The other is the saddle point on the deck lid centerline, where the reverse flow emerges. These differences between the CFD and experiment were possibly due to the unstable wake. This wake instability would be the reason of the differences between the Ford notchback model transverse vortices and the typical notchback car wake structures.