Aerodynamic Interference between Two Road Vehicle Models during Overtaking

Abstract

Using experimental (particle-image velocimetry and force measurement) and numerical tools [steady Reynolds-averaged Navier-Stokes (RANS) equations with the shear stress transport (SST) k-ω turbulence model], the overtaking maneuver between two identical vehicle models was examined. Considering the maneuver to be quasi-steady, one of the models (overtaken vehicle) was fixed while the other (overtaking vehicle) was set at various axial distances from the overtaken vehicle. The lateral clearance between the vehicles was constant and equal to 35% of the vehicles’ width. Due to the existence of an overpressure region upstream of the front of the overtaking vehicle, a side force was applied on the overtaken vehicle. Moreover, due to low pressures in the space between the two vehicles, a reduction in the base pressure of the overtaken vehicle caused an increase in its drag. Both forces and the yaw moment varied significantly when the front of the overtaking vehicle moved from the rear of the overtaken toward its front.