Abstract
An upswept aft body of vehicles can improve their aerodynamic performance. In order to study the effect of the upswept aft body, we examine flows around a two-dimensional rectangular cylinder with an upswept aft section in ground effects by means of RANS (Reynolds-Averaged Navier-Stokes) simulations. It is shown that an aerodynamic downforce increases due to the upswept aft section, since the flow between the cylinder and the ground is accelerated by a diffuser effect. Interestingly, the diffuser effect does not influence the total drag so much, because the drag increase of the upswept aft section is canceled by the drag reduction of a rear section of the cylinder.
