Simulation of the aerodynamic interaction of two generic sedans moving very closely

Computational fluid dynamics (CFD) was used to simulate the flow field over two generic sedans moving in sequence. The simulation was based on a steady state formulation and the focus of the simulation was to analyze the aerodynamic interaction of flow field around the two sedans. Detailed comparisons of aerodynamic feature of the corresponding parts were made among the first sedan, the second sedan and the sedan moving alone. Also, the structure of flow field around two sedans was illustrated and elaborated and was compared with the structure of flow field around single sedan. It was found that surface pressure distributions on the two sedans captured by the CFD analysis are remarkably different from that of single sedan in general. Furthermore, the flow structures obtained from the CFD calculations are always dependent on the corresponding distance between two sedans. Comparison for aerodynamic drags was carried out for the whole of the two sedans, each of the two sedans and single sedan. Both the surface pressure distributions and the flow structures show the same trends for the aerodynamic characteristics when the distance changes. This suggests that when vehicles move very closely, the aerodynamic interaction endangers the operating performance characteristics of the two sedans greatly.