风屏障对桥梁及车桥系统气动特性影响的数值研究

来源期刊:中南大学学报(自然科学版)2018年第7期

论文作者:何旭辉 周蕾 陈争卫 谢台中 敬海泉

文章页码:1742 - 1753

关键词:风屏障;车桥系统;横风;透风率

Key words:wind barrier; train-bridge system; crosswind; porosity rate

摘    要:利用数值模拟方法探究风屏障参数对流线型桥梁气动特性的影响;分析风屏障对不同桥型气动特性的影响并进行横向对比;讨论风屏障的透风率对车桥系统的气动特性以及流场的影响,通过分析车桥的三分力系数、压力云图、速度流线图、车桥表面风压分布以及风剖面等特征,揭示风屏障对车桥系统气动特性的影响机理。研究结果表明:风屏障能降低主梁上方的流速,从而减小列车的阻力和力矩,但同时也增加了桥的阻力,因此,安装风屏障可提高列车的行驶安全性但不利于桥梁抗风;针对流线型主梁断面,当风屏障高度为3 m且透风率为30%时为最优组合,此时车桥系统的阻力系数可达到最小值1.33;风屏障对不同桥型的遮蔽效应不同,相同的风屏障遮蔽效应对流线型主梁断面的影响远大于对钝体主梁断面的影响。

Abstract: The numerical simulation method was used to study the effects of wind barrier parameters(porosity rate and height) on aerodynamic characteristics of streamlined bridges. The influence of wind barriers on aerodynamic characteristics of different bridge types was systematically analyzed and compared laterally, and in addition, the influence of wind barriers on aerodynamic characteristics of train-bridge system and its flow field were discussed, the potential mechanism of wind barrier on the aerodynamic performance train-bridge system was revealed by analysing the characteristics of three-component force coefficient, pressure contour, velocity flow field, wind pressure distribution and wind profile. The results show that the wind barrier can reduce drag force and lift moment on the train, but also significantly increase the drag force of the girder since it declines the average flow velocity above the main beam. Therefore, the installation of wind barriers can improve the driving safety of the train but can be harmful for the wind resistance of the bridge. The optimal combination of wind barrier for streamlined bridge-deck section is 3 m with porosity rate of 30% since the drag force coefficient reaches the minimum value 1.33 in this case. The sheltering effect of wind barrier is different for different girder types, normally, the sheltering effect of the same wind barrier on streamlined bridge-deck section is much larger than that of bluff bridge-deck section.

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