The Effect of Rear Slant Angle on Vehicle Wakes and Implications for Platoons

Future Generation Intelligent Transport Systems (FGITS) will likely implement solutions to increase traffic density and thus throughput on existing infrastructures. Platooning (e.g. the close coupling of vehicles) may be a prominent feature of this solution, placing an understanding of near wake flows paramount to the FGITS case. However the notion of vehicles spaced at greater intervals is not only more commonly associated with present day conditions; it is furthermore characteristic of mixed-fleet conditions. These are likely to span the significant era between present day and complete FGITS fleets. Thus, far wake flows are similarly relevant.

Near and far wake analysis of a variable geometry Ahmed Model (a research form able to replicate structured wakes pertinent to practical vehicle flows) is used to explore relevant generic flow structures. The research presented here studies five configurations of the Ahmed Model (0°, 12.5°, 25°, 30°, 35° backlight angle), investigating the velocity deficit and turbulence intensity of a single model in near through far wake regions.

A study of the potential (given the magnitude and location of velocity deficit generated) for net drag reduction in intermediate and fully developed FGITS solutions is thus presented.