Computational analysis comparing aerodynamic performance of simplified sedan, wagon and SUV automobile configurations

Aerodynamic drag is a significant factor in the fuel efficiency of automobiles and alternative configurations, such as; sedans, wagons, and Sport Utility Vehicles (SUV) for example, are all expected to have significantly different aerodynamic characteristics. This study utilizes a Detached-Eddy Simulation to model the wake structure of the three previously mentioned vehicle configurations. The results indicate that an SUV and wagon can have approximately 30% and 15% more drag respectively than that of a comparable sedan and that the increase in drag can be attributed to the separation point from the roof of the vehicle due to the rear windscreen geometry. This has a significant impact on the formation of the C-pillar vortices and consequently the downwash and unsteadiness experienced in the wake of the vehicles.