CFD analysis for road vehicles - case study

This is a case study on the influence of the lower part of road vehicles on the global drag characteristics. Reducing overall drag by redesigning the lower part of the road vehicles has a potential of almost 20% in the overall drag breakdown, mainly due to the viscous effects and the fluidic interaction of the flow under the car with the typical bluff body flow pattern behind the vehicle. A special parameterization is proposed for the global shape of the sedan car, with respect to the lower part of the body, taking into account most of the specificities of the system. For such a complex interaction, CFD analysis is probably the only efficient tool in order to assess specific design parameterization of a generic car shape. Building on the credibility of such instruments is one of the major goals of this paper. Also, with respect to a target sedan car configuration, examples of successful design strategies are presented. Based on the CFD results, possible strategies to be used in order to reduce viscous drag and global drag characteristics are proposed