Influence of wind barrier on aerodynamic characteristics of vehicle on railway–highway combined bridge

Abstract

Wind barriers with different parameters will change the aerodynamic force of the car on the bridge as well as the stability of the vehicle–bridge system, affecting the vehicle’s safety and comfort. A numerical simulation test was conducted on the bridge-deck with three different air permeability wind barriers under three distinct vehicles of varying sizes and wind directions, with a large-span road–rail asymmetric cable-stayed bridge serving as the engineering foundation. The results show that the roll force of the bridge is proportional to the width of the body and inversely related to the height of the train. The roll force of a vehicle is inversely proportional to its height and width. The type of vehicle and the properties of the bridge deck exert minimal influence on the stability of the bridge when a single vehicle is positioned upstream. When a single vehicle is situated downstream, the tri-component force coefficient of the bridge undergoes significant changes, and the vehicle’s impact on the bridge’s stability becomes more pronounced. When the bridge deck’s ventilation rate is at 50%, the drag coefficient of the bridge deck doubles compared to that of a bare bridge deck, and the wind pressure coefficient of the vehicle surface on the bridge approaches zero. In scenarios involving two vehicles, the shielding effect caused by the vehicles positioned upstream and downstream results in a substantial shift in the aerodynamic forces acting on the two vehicles. This increases the wake width of the bridge and generates a visible vortex in the wake.