车辆外风挡结构对高速列车横风气动性能影响

采用三维、定常、不可压缩雷诺时均(navier-stokes, N-S)方程和重组化群(renormalization group, RNG) κ-ε双方程湍流模型,模拟3车编组高速列车气动性能。通过改变侧滑角研究不同风挡结构对列车气动性能影响。所选数值算法经过风洞试验验证,结果与试验数据变化规律一致,幅值相差不超过10%。不同风挡下列车表面压力系数沿车长分布规律一致,且幅值接近,风挡处车体表面压力系数差异显著,出现翻倍情况。随侧滑角增大,靠近风挡处列车表面压力系数分布发生明显变化。随侧滑角增大,不同风挡形式下的压力系数差异越显著,最大可达176%。随侧滑角增大,风挡的影响越显著;列车侧向力系数、升力系数和倾覆力矩系数的最大差异分别为17.71%、6.35%和7.52%;全封闭式风挡的列车抗倾覆能力相对最优,半风挡和平滑风挡对减小风环境下列车阻力有明显效果。

Effect of outside vehicle windshield on aerodynamic performance of high-speed train under crosswind

Three-dimensional steady uncompressible Reynolds-averaged N-S(Navier-Stokes)equation and RNG(renormalization group)κ-ε equation turbulence model were used to simulate the aerodynamic performance of the three-carriage high-speed train. The effect of outside vehicle windshield on the aerodynamic performance of high-speed train was studied by change the angle of sideslip. The results showed that testing results generated by the selected algorithm were in agreement with experimental data, and the deviation between them was below 10%. The distribution of the surface pressure coefficient along train was not affected by the windshield, and the amplitude of them had no significant differences. There was significant difference on distribution of the pressure coefficient around the windshield among different cases, and doubled pressure coefficient appeared in some occasions. With the sideslip angle increased, the difference among the six cases was more and more obviously, the maximum difference was 176%. With the increase of sideslip angle, the influence of windshield on lateral force coefficient, lift coefficient and moment coefficient was more significant, maximum differences were 17.71%, 6.35% and 7.52%, respectively. Anti-overturning ability of train with the total enclosed windshield was relatively optimal, and drag force of train with semi typed windshield and smooth typed windshield in wind environment were reduced obviously.