桥上典型车辆气动力特性风洞试验研究

Wind Tunnel Test and Research on the Aerodynamic Characteristics of Typical Vehicles on a Viaduct

近年来强侧风导致的汽车行车安全问题频繁发生,风致行车安全问题一直是风工程和汽车工程领域的研究热点。强风对车辆最直接的作用就是在车辆表面产生风荷载,风荷载是评价车辆行车安全的重要指标。以国内某山区高墩桥梁为研究背景,选择SUV、双层大巴、厢式货车和拖式货车等4种典型车辆,设计制作1∶15大比例尺车-桥系统风洞试验模型;通过系统风洞试验,研究桥上平风风速的空间变化规律和典型车辆的气动力特性。试验结果表明,防撞护栏显著降低护栏高度及以下区域的平均风速,同时在护栏高度以上局部位置产生加速区,最高风速达到自由来流风速的1.25倍。4种典型车辆气动力系数随风偏角的变化趋势有相似也有不同,例如4种典型车辆阻力系数均在风偏角20°左右取得最大值、在风偏角70°左右取得最小值;SUV升力系数与其他3类车辆明显不同。

In recent years, the strong cross wind has led to frequent driving safety problems of vehicles, and wind-induced driving safety has been a hot topic of research in the field of wind engineering and automotive engineering. The direct effect of strong wind on the vehicles is wind loads on the surface of vehicles, and the wind load is an important parameter to evaluate the driving safety. Taking a mountain viaduct in China as the research background in the paper, SUV,double-decker bus, van and tow truck are selected as four typical vehicles, and the vehicle and bridge models with a large scale ratio of 1∶15 are prepared to carry out wind tunnel tests. Through the wind tunnel test, the spatial variation law of average wind speed on the bridge and the aerodynamic characteristics of typical vehicles are explored. The results show that the crash barrier significantly reduces the average wind speed at area below the height of the barrier, while generating an acceleration zone at a local area above the barrier, with the highest wind speed reaching 1.25 times of the incoming wind speed. The major trends of aerodynamic coefficients are similar for the four typical vehicles. For example, the drag coefficients of the four typical vehicles all get the maximum value at the yaw angle of 20° and the minimum value at the yaw angle of 70°. However, the lift coefficients of SUVs are obviously different from those of the other three types of vehicles.