The Effect of Backlight Aspect Ratio on Vortex and Base Drag for a Simple Car-Like Shape

The vortex structure in the wake of a car creates drag. In the case of a simple wing this drag component is well defined as a function of lift, but for road vehicles the relationship is more complex. The backlight surface has been shown to be a significant source of vortex drag and in this paper the influence of backlight aspect ratio on both vortex and base drag is investigated. The vortex drag factor is found to be independent of aspect ratio, while the base drag component is shown to be dependent on the ratio of base to frontal area.