强侧风对时速350 km高速列车气动性能影响分析

Influence of Strong Crosswind on Aerodynamic Performance of High Speed Train at the Speed of 350 km/h

采用NURBS曲面设计方法完成对某型高速列车头车的三维数字化设计建模,基于三维定常不可压的黏性流场N-S及k-ε着方程湍流模型,利用有限体积数值模拟方法分析计算出列车的速度阻力函数关系,同时针对列车在不同风向角的强侧风环境中运行时压力场和速度场做了进一步研究。研究发现:在无风明线上运行时列车所受空气阻力与运行速度的平方成正比,侧风运行时随着风向角的扩大空气阻力系数呈现先增大后逐渐下降的变化趋势。流场分布结构复杂不规律,当侧风情况较为严重时正压区主要分布在迎风侧,负压区主要分布在背风侧和车顶部位,且负压表现更为强烈,列车前端滞止点向迎风侧发生偏移,致使迎风侧与背风侧产生巨大压差。

This study adopted the NURBS surface design method to complete 3D digital design modeling of a high speed train headstock.Based on the turbulent model of the three-dimensional,steady,incompressible,viscous flow field N-S and k-εequations,the finite-element-volume numerical simulation method was used to analyze and calculate the relationship between train speed and air resistance.At the same time,further analysis of the pressure field and velocity field of the train operating in strong lateral wind environments with different wind direction angles was conducted.The study found that the air resistance of the train was proportional to the square of the running speed when the train was running in a wind-free long straight railway line.When the wind was running in the crosswind,the air resistance coefficient increased first and then gradually decreased with the expansion of the wind angle.The distribution structure of the flow field was complex and irregular.When the crosswind condition was more serious,the positive pressure zone was mainly distributed on the windward side of the train,while the negative pressure zone was mainly distributed on the leeward side and the top of the train,and the negative pressure performance was more intense.The front-end stagnation point of the train shifted toward the windward side,resulting in a huge pressure difference between the windward side and the leeward side.