Truck platooning is an emerging technology that exploits the drag reduction
experienced by bluff bodies moving together in close longitudinal proximity. The
drag-reduction phenomenon is produced via two mechanisms: wake-effect drag
reduction from leading vehicles, whereby a following vehicle operates in a
region of lower apparent wind speed, thus reducing its drag; and base-drag
reduction from following vehicles, whereby the high-pressure field forward of a
closely-following vehicle will increase the base pressure of a leading vehicle,
thus reducing its drag.
This paper presents a physics-guided empirical model for calculating the
drag-reduction benefits from truck platooning. The model provides a general
framework from which the drag reduction of any vehicle in a heterogeneous truck
platoon can be calculated, based on its isolated-vehicle drag-coefficient
performance and limited geometric considerations. The model is adapted from
others that predict the influence of inter-vehicle distance for vehicle
platoons, but extends the concept to account for cross winds and for lateral
offsets between sequential vehicles, thus permitting its use for a range of
modelling and simulation applications. Good agreement with experimental data
sets from wind-tunnel and track tests is demonstrated in the paper.