Study on the Dynamic Instability of a Bus in Crosswind Conditions

Abstract

When a grand bus moves on the road, aerodynamic forces and moments can be the leading cause of vehicle instability and accidents. Therefore, studying the influence of aerodynamic forces and moments on the instability of grand buses is a matter of concern. This article investigates bus' safety when moving in crosswind conditions with three types of motion instability: loose contact, rollover, and sideslip. A static model is used to determine the speed limits when the vehicle is unstable. The basic equations are selected based on the assumption that the vehicle moves straight in the driving line on the road. The aerodynamic forces and moments are characterized by the aerodynamic coefficients determined by the bus's aerodynamic simulation model. The article has focused on determining the limit speeds of crosswinds that cause instability of the 45-seat bus by numerical method. The study results can be used as a basis for assessing the influence of aerodynamic forces on the dynamic instability of the bus during the movement on the road in complex windy conditions.