Analysis of the Aerodynamic Characteristics of Small-Sized Car Vehicles under the Influence of Steady Crosswind

Abstract

The crosswind is one of the factors that can lead to a car accident. Crosswind is defined as a side force that causes a vehicle to become unstable and deviate from its desired path. This article focuses on evaluating the flow behaviour and aerodynamic loads that affect vehicle stability when driving in a steady crosswind. In this study, a numerical approach is used with the ANSYS Fluent software as a platform to run the simulation. In this research, the crosswind flow angle (Ψ) is varied from 0° to 90°. The incompressible flow surrounding the vehicle is solved using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunctions with the k-ε turbulence model. The Reynolds number is utilized depending on the velocity of the vehicle which are 2.8×106 for high Reynolds number and 7.2×105 for low Reynolds number respectively. According to the findings, the crosswind has a significant quantitative and qualitative impact on aerodynamics. In terms of aerodynamic load, the side coefficient (Cs) increases as the crosswind yaw angle increases. When the crosswind yaw angle reaches 60°, there is a significant drop, but it remains almost constant when the crosswind yaw angle reaches 90°. In terms of flow structure, as the crosswind yaw angle increases, the vortex formation on the leeward region expands, increasing the vehicle stability imbalance. Finally, there is no significant difference in the quantitative aerodynamic characteristics of high and low Reynolds numbers.