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给出了列车穿越带有缓冲结构的隧道压力变化的三维粘性流场数值模拟过程,控制方程为三维粘性、可压缩、非定常流的N-S方程,空间离散采用了中心有限体积法格式,时间采用预处理二阶精度多步后差分格式进行离散,对列车与隧道之间的相对运动采用移动网格技术处理。对不同的缓冲结构缓解隧道内瞬变压力及压力梯度的作用进行了研究。研究结果表明,缓冲结构的设置能够有效地降低隧道内的压力和压力梯度的最大值,其原因在于缓冲结构延长了压缩波压力上升的时间,降低列车突入隧道时所形成的最大压力梯度;另一方面由于压缩波在缓冲结构和列车、隧道之间多次的反射,也降低了压力峰值。
The numerical simulation of three-dimensional viscous flow field through the tunnel with buffer structure is given. The governing equations are three-dimensional viscous, compressible and unsteady NS equations. The spatial finite element method is adopted for the spatial discretization. Preprocessing second-order accuracy multi-step difference scheme is discretized, and the relative movement between train and tunnel is handled by moving grid technology. The effects of different buffer structures on relieving transient pressure and pressure gradient in the tunnel were studied. The results show that the cushioning structure can effectively reduce the maximum pressure and pressure gradient in the tunnel. The reason is that the cushioning structure prolongs the compression wave pressure rise time and reduces the maximum pressure gradient formed when the train enters the tunnel. On the one hand, pressure peaks are also reduced due to the multiple reflections of the compressional waves between the buffer structure and the train and tunnel.