CFD Investigation on the Aerodynamic Characteristics of a Heavy Vehicle Travelling under Crosswind Conditions

The handling stability of heavy tractor semi-trailers under crosswind conditions is crucial for road safety due to their large side area and exposure to variable road conditions. Crosswinds can cause lateral forces and moments on the vehicle, affecting its stability and making it harder to control. In this present work, numerical simulation is performed to study the crosswind effects on the handling stability of a tractor semi-trailer. The aerodynamic characteristics of the tractor semi-trailer under different crosswinds were computed by computational fluid dynamics (CFD). The study focused on the HINO 700 Series heavy truck model, using three different configurations: side skirt, cab side fairing and cab roof fairing. To completely investigate the vehicle's aerodynamic response, the crosswind conditions were systematically changed at yaw angles of 0°, 15° and 30°. The results indicate that for no crosswind conditions, trucks with cab side fairing have the best design. While for crosswind conditions, trucks with roof fairing have a better design. The aerodynamic characteristics are significantly influenced by various configurations and the angle of the crosswind. However, different truck configurations have a significant impact on truck stability, such as the drag force coefficient (Cd) and side force coefficients (Cs). It shows how a truck with an additional component will have a larger surface area and a higher side force coefficient in crosswind conditions. In terms of appearance, vortices formation on the front of the truck cabin and the leeward side of the truck body is more affected by rising crosswind angles. Therefore, it indicates that the various truck configurations and crosswind angles play a critical role in determining the safety of truck operations.