Effect of Crosswind on Drag and Lift Variations during Mixed-Vehicle Overtaking Manoeuvres: A CFD Approach

A CFD-based analysis is carried out in this study to examine time-dependent aerodynamic effects during highway overtaking manoeuvres, with a primary focus on truck-truck interactions under crosswind conditions. Using ANSYS Fluent and unsteady Reynolds-Averaged Navier-Stokes (RANS) simulations, the time-resolved aerodynamic behaviour of a truck being overtaken by an identical vehicle is investigated in detail. A secondary case involving a passenger car overtaking the truck is also examined for comparative purposes. The analysis concentrates on the evolution of the drag and lift coefficients of the overtaken truck throughout the overtaking process. Results indicate that truck-truck interactions produce stronger aerodynamic disturbances, with greater fluctuations in drag and lift compared to the car-truck scenario. These effects are strongly dependent on vehicle spacing and relative positioning. The findings highlight the critical role of transient aerodynamic loading in the design and operation of heavy-duty vehicles, particularly in mixed traffic environments and crosswind-prone areas. This research advances the understanding of real-world aerodynamic interactions, with implications for fuel efficiency, dynamic stability, and highway safety.