With the continuous improvement of train speeds, aerodynamic braking is a good choice to effectively reduce the braking distance. In this study, unsteady aerodynamic characteristics of vehicles with braking plates inside and outside the tunnel were evaluated by CFD using an improved delayed detached eddy simulation (IDDES). Mesh convergence studies were also performed, and results were compared with two wind tunnel tests to verify the numerical method. By comparing and analyzing the effect of plates on the force, braking distance, and flow field around vehicles inside and outside the tunnel, it is found that the aerodynamic braking force of vehicles inside and outside the tunnel increases nearly 1.5 times and 2.2 times due to the opened plates, respectively. The positive lift force of vehicles is also increased, especially inside the tunnel, which reduces the friction between the wheels and rail tracks. The opened plates also cause the formation of many vortices with excessive energy, which may aggravate the vehicle vibration and noise, especially inside the tunnel. By comparing the impact of the operating environment (inside or outside the tunnel) on the aerodynamic characteristics of each vehicle, it is also found that the closer the vehicle to the downstream, the more sensitive it is to the tunnel. The findings of this study can help to design the braking plate and guide the operation of rail vehicles.

随着列车速度的不断提高，气动制动是有效缩短制动距离的理想选择。在这项研究中，使用改进的延迟分离涡流仿真（IDDES）通过CFD对隧道内外带有制动板的车辆的非定常空气动力学特性进行了评估。还进行了网格收敛研究，并将结果与​​两个风洞测试进行比较以验证数值方法。通过比较和分析板对隧道内外车辆的力，制动距离和流场的影响，发现隧道内外车辆的空气动力增加了近1.5倍和2.2倍。分别打开的板。车辆的正向提升力也会增加，尤其是在隧道内部，这样可以减少车轮和铁轨之间的摩擦。打开的板还会导致形成带有过多能量的许多涡流，这可能会加剧车辆的振动和噪音，尤其是在隧道内部。通过比较操作环境（在隧道内部或外部）对每辆车的空气动力特性的影响，还发现车辆越靠近下游，对隧道越敏感。这项研究的发现可以帮助设计制动盘并指导轨道车辆的运行。通过比较操作环境（在隧道内部或外部）对每辆车的空气动力特性的影响，还发现车辆越靠近下游，对隧道越敏感。这项研究的发现可以帮助设计制动盘并指导轨道车辆的运行。通过比较操作环境（在隧道内部或外部）对每辆车的空气动力特性的影响，还发现车辆越靠近下游，对隧道越敏感。这项研究的发现可以帮助设计制动盘并指导轨道车辆的运行。