An Investigation of Aerodynamic Characteristics of Three Bluff Bodies in Close Longitudinal Proximity 2019-01-0659
The benefit in fuel-saving for road vehicles travelling in close longitudinal proximity stems from the potential reduction in total aerodynamic drag compared to the sum of that for the same number of vehicles when travelling alone.
Research in the 1980s considered travelling in close proximity, termed “platooning”, as a means for reducing congestion, but the aerodynamic drag reduction and fuel-savings found in wind tunnel tests and road-trials became the primary focus of further investigations. Practical application was limited by the lack of systems to control vehicle spacing which was critical to the aerodynamic efficiency of the platoon and for safety. However, vehicle communication and control systems associated with the recent development of connected and autonomous vehicles has provided greater opportunity for platooning to be considered again within future traffic management systems.
Early research involving passenger cars, and also more recent studies using heavy goods vehicles, has been based on ‘vehicle spacing’ as the test variable. Platoons were of homogeneous constituents and the aerodynamic characteristics of most vehicles in these studies comprised large separated wakes – an ideal situation for ‘shielding’ vehicles in close proximity. Yet most passenger vehicles, and an increasing number of commercial vehicles, are being designed for minimum drag when travelling alone and consequently have an objective of minimising the size of the separated wake. Thus, these may not be ideally suited to platooning applications.
This paper will present results from an experimental investigation to show the effect of systematic changes in upper-body geometry on the aerodynamic characteristics of three Windsor models in close proximity. This work was part of an on-going project to consider the effect of styling on vehicles travelling in platoons.
Geoffrey Le Good, Peter Boardman, Max Resnick, Brian Clough