中文摘要：

由于占据了部分隧道空间，列车在运行时会产生活塞作用效应，列车周围的流场和压力场均发生变化，造成了隧道与外部空间的空气交换．为了找出列车相会时活塞效应的关键因素，根据粘性流体力学的非稳定流理论，分析了列车在隧道内的运行情况，采用相对坐标法建立了列车相会时的活塞风数学模型，提出了在自然风速影响下列车相会以及减速相会时的活塞风速计算方法．结果表明，列车活塞效应的影响因素主要有隧道净空尺寸、自然风速和阻塞比等．

英文摘要：

For taking part space of tunnel by train, the change of flow and pressure field which is caused by piston effect of train leaded to the exchange of airflow between tunnel and outside. In order to find out the key factors of piston effect, according to the unsteady flow theory of viscous fluid mechanics, train operation in tunnel is analyzed in the paper. Basing on relative coordinate method mathematical model of piston effect is founded, and theoretical calculation of piston wind caused by train meeting under the influence of natural wind is put forward. Results indicated that blockage ratio, tunnel cross - section, train speed and natural wind speed are the major factors of piston wind.