A Study on Aerodynamic Drag of a Semi-trailer Truck

The primary objective of this study is to determine the aerodynamic impact of various fuel saving devices used in a commercial vehicle (i.e., semi-trailer truck). To measure the aerodynamic drag produced by the vehicle, a wind tunnel study was undertaken using a 1/10th scale model truck. The aerodynamic drags on the baseline vehicle including different external attachments (i.e., front faring, side skirting and gap filling) were measured for a range of vehicle operating speeds and yaw angles, and with different combinations. The results show that these external attachments (fairing and covering) have notable impact on aerodynamic drag as they can reduce up to around 26% aerodynamic drag over the baseline model depending on cross wind effects. The full-skirting (using the front fairing, side skirting and gap filling) has maximum impact whereas only front fairing has minimum impact on aerodynamic drag reduction.