## 4 Conclusions  
In this study, we analyzed the aerodynamic characteristics of platooning using a SolidWorks Flow Simulation for four types of vehicles. By implementing the interaction between the low pressure generated at the rear of the leading vehicle and the high pressure generated at the front of the following vehicle through platooning, the characteristics of the change in the drag coefficient of the following vehicle due to the shape and distance were analyzed. (1) In most models, the stagnation pressure generated at the front of the following vehicle is suppressed by the low pressure at the rear of the leading vehicle, and the drag coefficient of the following vehicle is generally reduced. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Front**} & \multicolumn{3}{c}{**Effect on Drag Coefficient Reduction**} \\ \hline \multirow{2}{*}{**Front shape of**} & \multirow{2}{*}{**Front** element**} & \multicolumn{3}{c}{The high-speed, low-pressure wake of} \\  & & & the leading (front) vehicle is suppresses the Bernoulli effect at the front of the following vehicle. \\ \hline \multirow{2}{*}{**Front area of rear vehicle**} & \multirow{2}{*}{(a) Front element} & The large area at the front is continuously influenced by the wake of the leading vehicle, increasing the drag coefficient reduction. \\ \hline \multirow{2}{*}{**Rear shape of**} & \multirow{2}{*}{**Front vehicle**} & \multirow{2}{*}{(b) Rear element} & The drag coefficient reduction of \\  & & & following (rear) vehicles is diminished by \\  & & & washing the wake generated by the rear \\ \hline \multirow{2}{*}{**Rear area of front vehicle**} & \multirow{2}{*}{(b) Rear element} & The drag coefficient reduction of the \\  & & & following vehicles increases due to the \\  & & & wide, low-pressure range formed at the \\  & & & rear of the leading vehicle. \\ \hline \multirow{2}{*}{**Overall height of**} & \multirow{2}{*}{**Overall height of**} & \multirow{2}{*}{(c) height element} & The large height creates a distribution of \\  & & & low pressures above the rear, reducing \\  & & & the influence of the low pressures at the \\  & & & rear of the leading vehicle depending on \\  & & & the height of the following vehicle. \\ \hline \multirow{2}{*}{**Overall height of**} & \multirow{2}{*}{(c) height element} & The small height escapes from the effects \\  & & & of the wake of the leading vehicle more \\  & & & quickly and reduces the effect of the rear \\  & & & vortex as the separation \\  & & & distance increases. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Effect of the shape of vehicles on drag coefficient reduction. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Front Vehicle Type**} & \multicolumn{3}{c}{**Rear Vehicle (PBV) Drag Coefficient (C\({}_{d}\)) [Single C\({}_{d}\) = 0.266]**} \\ \cline{2-5}  & **1 m** & **5 m** & **10 m** & **15 m** & **20 m** \\ \hline \multirow{2}{*}{**Small SUV**} & 0.279 & 0.242 & 0.235 & 0.236 & 0.236 \\  & 0.244 & 0.218 & 0.238 & 0.274 & 0.305 \\  & 0.381 & 0.335 & 0.305 & 0.267 & 0.267 \\  & 0.171 & 0.189 & 0.193 & 0.213 & 0.220 \\ \hline \multirow{2}{*}{**Front Vehicle Type**} & \multicolumn{3}{c}{**Rear Vehicle (Truck) Drag Coefficient (C\({}_{d}\)) [Single C\({}_{d}\) = 0.767]**} \\ \cline{2-5}  & **1 m** & **5 m** & **10 m** & **15 m** & **20 m** \\ \hline \multirow{2}{*}{**Small SUV**} & 0.572 & 0.577 & 0.619 & 0.702 & 0.748 \\  & 0.498 & 0.461 & 0.458 & 0.451 & 0.462 \\  & 0.456 & 0.535 & 0.586 & 0.628 & 0.636 \\  & 0.222 & 0.347 & 0.424 & 0.493 & 0.529 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._As small and medium SUVs exhibit similar shapes at the front, their drag reduction trends are similar. When the separation distance exceeds 15 m, the drag coefficient remains constant. Beyond a separation distance of 15 m, the following vehicle is judged to be unaffected by the wake of the leading vehicle. 3. When the medium SUV is used, the resulting upwash is the most prominent feature.