# A Study on Aerodynamic and Structural Design of Fairing Using Glass Fabric Composite Structure
## 2 Requirement of Design  
### Target of Design  
As a result of checking studies on drag reduction for vehicles operated in Korea, the studies were performed mostly for cars and vans used for personal purposes. It is considered to be different because for commercial vehicles centered on performance, such as freight transport capacity, their size and external shape are almost standardized, while vehicles for personal purpose have various sizes and shapes. As mentioned above, commercial vehicles are standardized according to their transport capacity, and mostly delivery service and food resource circulation uses small and medium-sized ones (1-3.5 ton), and the vehicles transporting construction machinery consist of large ones (5-20 ton). In Korea, COVID-19 and the spread of digital culture led to the increase in indirect transactions, which are purchase online, rather than direct ones, in which people go to the market and purchase things. Accordingly, transport companies are directly building and operating delivery transport systems (HUB), etc., to increase transport efficiency. There was a significant rise in the use of small and medium-sized commercial vehicles that are relatively efficient to operate in the city by such a delivery transport system. This study was carried out for 3.5-ton class commercial vehicles among small and medium-sized ones. To perform actual design and analysis on 3.5-ton class commercial vehicles selected for the study target, 6.6 freezer mighty from the Korean 'H' company in Seoul, Republic of Korea was selected for the detailed application model. Table 1 shows the specification of the vehicle to be applied to the study [11]. Figure 1 shows a 3D view of the conceptual aerodynamic configuration. This study carried out design and analysis on the optimum fairing, which could reduce the drag of commercial vehicles. The requirement for this is as shown in Table 2. As a result of reviewing studies on the fairing performed until the present in Korea, it was confirmed that the drag reduction effect of the fairing was about 15-19%. Therefore, this study set up a goal that the effect of fairing becomes 19% or more, which is the highest level in Korea. The size of the fairing is restricted in length and width by the target vehicle's cab roof size and in height by the space between the loading container top and the cab roof. \begin{table}
\begin{tabular}{c c} \hline \hline
**Specification** & **Value** \\ \hline \hline \begin{tabular}{c} Overall length \\ \end{tabular} & 6735 mm \\ \hline \begin{tabular}{c} Overall width \\ \end{tabular} & 2230 mm \\ \hline \begin{tabular}{c} Overall height \\ \end{tabular} & 3180 mm \\ \hline \begin{tabular}{c} Container size \\ \end{tabular} & \begin{tabular}{c} Length \\ \end{tabular} & 5100 mm \\ \hline \begin{tabular}{c} Container size \\ \end{tabular} & \begin{tabular}{c} Width \\ \end{tabular} & 2280 mm \\ \hline \begin{tabular}{c} Wheel base \\ \end{tabular} & \begin{tabular}{c} Height \\ \end{tabular} & 2200 mm \\ \hline \begin{tabular}{c} Cab roof area size \\ \end{tabular} & \begin{tabular}{c} Length \\ \end{tabular} & 1350 mm \\ \hline \begin{tabular}{c} Cab roof area size \\ \end{tabular} & \begin{tabular}{c} Width \\ \end{tabular} & 1410 mm \\ \hline \
\begin{tabular}{c} Height \\ \end{tabular} &
\begin{tabular}{c} 870 mm \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 1: Specification of target vehicle. Figure 1: 3D view of conceptual aerodynamic configuration. In aerodynamic design, 80 km/h, the normal fuel efficiency driving speed on the highway, was applied to the vehicle speed in design and analysis for the optimum performance. In the structural design, for the vehicle speed in design and analysis, the highest driving speed and gust condition as in Table 3 were considered together to perform the analysis. The highest driving speed of commercial vehicles equipped with the fairing was set as 130 km/h.