风障对桥塔附近桥面汽车气动力特性的影响

INFLUENCE OF WIND BARRIER ON AERODYNAMIC CHARACTERISTICS OF AUTOMOBILES ON BRIDGE GIRDER NEAR PYLON

强横风下大跨缆索承重桥梁的桥塔附近桥面风环境交替变化显著,极易导致汽车侧向失稳事故,针对途经桥塔附近桥面汽车气动力特性的研究对评价汽车侧向操纵稳定性尤为重要。该文进行了某分离钢箱梁斜拉桥独柱式桥塔附近桥面汽车模型测力风洞试验,获得了横风下汽车途经桥面不同位置时气动力特性的一般规律。设置风障前后桥塔附近桥面汽车气动力系数对比分析表明:风障可显著减小该类桥型塔区桥面汽车的侧力系数和横摆力矩系数,可减小大体量汽车的侧倾力矩系数和中、小体量汽车横摆力矩系数的变化幅值,风障对提高大风天途经桥塔附近桥面汽车的侧向稳定性作用明显。

Lateral instability accidents of automobiles are most easily overdone due to the alternative wind environment above the girder near the pylon of a long-span cable-supported bridge in a strong crosswind. Therefore, the investigation of aerodynamic characteristics of automobiles passing by the girder near a pylon is very helpful for the assessment of lateral control stability of automobiles. The aerodynamic measurement on an automobile＇s model on the steel split-box girder near the pylon of a cable-stayed bridge with a single columns carried out by a wind tunnel test. The rule of aerodynamic characteristics of an auto on different positions on the deck in a crosswind is obtained. Considering a wind barrier or not, the comparison and analysis of aerodynamic coefficients of autos near the pylon shows that the aerodynamic coefficients of the side force and yaw moment of vehicles on this type of girder near the single column could be significantly reduced by a wind barrier, and some other values could also be smaller, such as the rolling moment coefficient of a large automobile and the variable amplitude of yaw moment coefficients of medium or small automobiles. Obviously, a wind barrier is very useful for improving the side control stability of vehicles passing by the girder near a pylon.