中文摘要：

在简化列车外形的情况下，针对列车在不同风速下的气动力进行计算。为计算气动力，将三维雷诺平均N-S方程（RANS）结合k-ε湍流模型，用有限体积法将控制方程离散求解。用SIMPLE法耦合压力-速度场。在得出气动力的基础上，使用本文推导的横风作用下列车通过曲线轨道的限制速度公式，分析了气动升力、气动阻力对限制速度的影响。模拟计算结果显示，增大列车运行速度或横风速度都会增大列车的气动升力和气动阻力，并使之呈非线性增大的趋势。列车在高速、大横风情况下运行，以上2种非线性风险的影响使行车的安全性受到严重的威胁。升力的作用一般使列车通过曲线轨道的限制速度降低，而阻力对限制速度的影响主要取决于风向。

英文摘要：

Aerodynamic forces and moments coefficents of flows past a simplified train geometry under different wind speeds are investigated. To compute numerically the different coefficents, combining the three-dimensional Reynolds-averaged Navier-Stokes equations（RANS） with the k-ε turbulence model, the control equation is solved with the finite volume technique. The pressure-velocity fields are coupled using the SIMPLE algorithm. At each iteration the pressure correction is obtained by solving a velocity divergence-derived Poisson-like equation. With the computed aerodynamic forces, the formula of the limit speed of trains negotiating curves under side winds is deduced and applied to analyse the influences of aerodynamic forces on the limit speed of the train. Results of numerical investigations show the aerodynamic lift and overtune moment increase more and more rapidly along with increasing of the train speed and wind speed. The enhancement trends show nonlinear phenomena. When a train travels in high speeds and encounters huge side winds, the two nonlinear risks extremly impair the safety of the train. The aerodynamic lift reduces the limited train speed, the influences of the aerodynamic resistance on the limited train speed rest on the direction of wind flow.