侧风风场特征,如均匀风和大气底层边界速度型对高速列车在侧风环境下运行的安全性评估有直接影响.为了准确地评估侧风对在平原上运行的高速列车的影响,基于三维定常可压缩流动的NS方程,采用SSTk-ω两方程湍流模型和有限体积法,对时速350 km的动车组在均匀风和大气底层边界速度型风场中的流场和气动力特性分别进行了数值模拟计算和分析.结果表明:对在平原上运行的高速列车而言,作用于列车的气动升力、侧向力及倾覆力矩均随侧风风向角的增大而迅速增大;当风场为大气底层边界速度型时,列车顶部与底部及两个侧面的压力差小于风场为均匀风时的压力差,侧向力及倾覆力矩均小于风场为均匀风时的力及力矩,升力则随侧风风向角的增加具有不确定性.采用均匀风场评估高速列车在平原侧风环境中运行的安全性,会高估侧风对列车运行安全影响的风险,使得过低地限制列车的安全行驶速度,从而影响列车的正常运行效率.建议采用大气底层边界速度型风场进行评估.%Characteristics of the cross wind field, such as uniform winds and lower atmospheric boundary layer winds,have directly influence on the operation safety of high-speed trains which run in the cross wind environment. In order to accurately assess the effect of cross winds on trains running on plains,on the basis of the three-dimensional steady compressible flow of NS equations, using the SST k-ω two-equation turbulence model and finite volume method, the flow field and aerodynamic characteristics of the high speed train running at 350 km/h in the cross wind field of uniform winds and lower atmospheric boundary layer winds were simulated numerically and analyzed. The results show as follows:For a high-speed train running under cross winds on a plain, the aerodynamic lift force, lateral force and overturning moment acting on the train increase rapidly with increasing of the wind direction angle; when the train runs through the lower atmospheric boundary layer, compared to the uniform wind filed, the pressure differences of the train at the top & bottom and on two sides are less, the lateral force and overturning moment are also less, and the aerodynamic lift force is of uncertainty in the ease of increasing of the wind direction angle. Using the uniform wind field for evaluation of operation safety of high-speed trains running under cross winds on a plain will overestimate the risks cross winds may bring about in train operation and will over limit the train speed so that the normal train operation efficiency is affected. The lower atmospheric boundary layer winds are suggested to be used for evaluation of the aerodynamic performance of a train.
展开▼
