Aerodynamic interactions between two 30%-scale passenger vehicles in close
proximity were examined experimentally in a large wind tunnel, with a focus on
longitudinal separations up to two vehicle lengths, lateral separations up to
one lane width, and combinations thereof. Part 1 of this paper described the
longitudinal following (platooning) configurations of these results, while this
paper concentrates on adjacent-lane influences and lateral-offset effects when
platooning at a single separation distance. Test models were based on the
DrivAer and Aero-SUV open-access geometries, each with slant-back (Notchback or
Fastback) and square-back (Estateback) variants. This provided four distinct
model pairings, not all of which were tested in each positional arrangement.
Adjacent-lane results matched the trends from a smaller-scale study in a
different wind tunnel using the same geometry pair, with small-but-distinct
differences attributed to different blockage ratios in the two wind-tunnel
studies. For three specific adjacent-lane arrangements, no significant
differences were observed when changing the back variants of either of the
models, suggesting that these proximity effects are primarily a function of
model size, not shape. Four model pairs were tested with lateral offsets of
0.00, 0.25, 0.50 and 1.00 lane-widths, corresponding to approximately 0, 0.5,
1.0, and 2.0 model widths, at a longitudinal separation distance of 0.5 model
lengths. The data suggest that, as crosswinds increase, peak drag reductions
from platooning can be maintained by offsetting the vehicles laterally to
maintain the follower model in the wake of the lead model, but the effect is
sensitive to the shape of the lead vehicle. At 15° yaw angle, a quarter-lane
offset (half-width offset) can maintain the system drag reduction at this
separation distance.