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结合正在建设的实际工程项目,采用数值计算方法对曲线隧道内行车间距及车速对活塞效应的影响进行分析。结果表明:汽车进入隧道和驶出隧道时,隧道断面平均风速明显增大;当汽车在隧道内行驶时,汽车与隧道壁面的环状空间及尾部内均出现了强烈的回流及涡流现象;行车间距的增加有利于提高汽车有效阻力系数,增强汽车产生的活塞效应。在相同的行车间距下,较高的车速有利于提高汽车产生的活塞风,但队列下游行驶的汽车将严重的受到上游行驶汽车尾流的影响,导致汽车阻力系数的下降。
Combined with the actual construction project under construction, the numerical calculation method is used to analyze the influence of the distance between the traffic lane and the piston speed on the curve tunnel. The results show that when the car enters the tunnel and exits the tunnel, the average wind speed of the tunnel cross section obviously increases. When the car travels in the tunnel, there are strong backflow and vortex phenomenon in the annular space and the tail of the car and the tunnel wall. Increasing the distance is conducive to improving the effective resistance coefficient of the car and enhancing the piston effect produced by the car. Under the same driving distance, the higher speed will help to improve the piston wind generated by the car. However, the cars traveling in the downstream of the queue will be seriously affected by the wake of the upstream driving vehicle, resulting in the drop of the car’s drag coefficient.