西部山区某悬索桥桥址处风环境实测及CFD数值模拟

发布时间：2018-01-15 08:31

本文关键词：西部山区某悬索桥桥址处风环境实测及CFD数值模拟　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：进入21世纪后,我国基础设施建设日益加快,交通网络越来越复杂。尤其是西部开发战略的实施,使得我国西部建设焕发新的生机,大型桥梁建设,跨度越来越大,型式越来越多样化。然而由于西部山区本身地形的复杂性,导致地区风场特性差异较为明显,而对于大跨度桥梁而言,桥梁抗风始终是整个桥梁设计的重中之重,对于合理确定桥梁设计的基本风速,桥梁风剖面,以及桥梁脉动风特性是桥梁设计者考虑桥梁结构风致振动的基础,也是桥梁抗风设计的首要问题。本次风场研究工作是以寸滩长江大桥(主跨880米的悬索桥)的建设为依托,通过对现场实测风速数据的分析以及利用大型流体计算软件Fluent进行桥址区风场数值模拟来求得风场特性参数。从现场风速实测分析,主要是通过对现场桥塔施工塔架外伸角钢每隔10米安装风速仪,并将风速采集仪安置在塔架中间,连续采集风速数据,对风速数据进行相应的统计分析,以得到桥址区实测的风场特性。主要的风场特性包括脉动风特性及平均风特性。平均风特性包括确定100年重现期下的基本风速,平均风向角、平均风攻角随时间的变化规律和风玫瑰图;脉动风特性则主要研究了脉动风速的湍流强度、阵风因子,紊流积分尺度以及采用和规范相一致的风速谱拟合得到桥址区实际风速功率谱。从数值模拟角度分析风场特性,首先利用Google地图精确的导出桥址区三维地形坐标值,再利用逆向软件imageware对上面得到的三维坐标进行自由曲面拟合,得到桥址区的地形图,将得到的地形图再次导入到Fluent的前处理软件Gambit中建立桥址区风场模型,然后利用其网格划分功能对数值风场实现网格划分操作,完成后将Mesh文件导出,然后再Fluent中设置相关计算参数,利用Fluent自带的编程UDF实现入口风剖面的导入,实现对三维风场的计算,最后导出桥面处速度云图等一系列重要计算结果。对计算得到的结果与实测数据分析的结果以及规范值进行对比分析,得到桥址处风环境特性参数。
[Abstract]:After 21th century, the infrastructure construction of our country is accelerating day by day, the traffic network is more and more complex. Especially, the implementation of the strategy of western development makes the western construction of our country radiate new vitality, the large-scale bridge construction. However, because of the complexity of terrain in the western mountainous area, the difference of wind field characteristics is obvious, but for the long-span bridge. Bridge wind resistance is always the most important part of the whole bridge design. The basic wind speed, the bridge wind profile and the bridge pulsating wind characteristics are the basis for bridge designers to consider the wind-induced vibration of bridge structure. The wind field research work is based on the construction of the Putan Yangtze River Bridge (the main span of the suspension bridge of 880 meters). The wind field characteristic parameters are obtained by analyzing the field wind speed data and using the large-scale fluid calculation software Fluent to simulate the wind field in the bridge site. It is mainly through installing anemometer every 10 meters to the tower frame extension angle steel in the construction of the bridge tower on the spot and placing the wind speed collector in the middle of the tower to collect the wind speed data continuously and to carry on the corresponding statistical analysis to the wind speed data. The main wind field characteristics include pulsating wind characteristics and average wind characteristics. The average wind characteristics include the determination of the basic wind speed and the average wind direction angle during the 100-year recurrence period. The variation of the mean wind attack angle with time and the wind rose chart; The characteristics of pulsating wind are mainly studied on turbulence intensity and gust factor of pulsating wind speed. The actual wind power spectrum of bridge site is obtained by fitting the turbulent integral scale and wind speed spectrum which is consistent with the standard. The wind field characteristics are analyzed from the point of view of numerical simulation. Firstly, the 3D terrain coordinates of the bridge site are accurately derived by Google map, and then the 3D coordinates are fitted by the reverse software imageware. The topographic map of the bridge site area is obtained, and then the topographic map is imported into the pre-processing software Gambit of Fluent to establish the wind field model of the bridge site area. Then the meshing operation of numerical wind field is realized by using its mesh division function, and the Mesh file is exported after completion, and then the relevant calculation parameters are set in Fluent. The introduction of inlet wind profile and the calculation of 3D wind field are realized by using Fluent's own programming UDF. Finally, a series of important calculation results, such as velocity cloud map at the bridge deck, are derived. The calculated results are compared with the analysis results of the measured data and the standard values, and the wind environment characteristic parameters at the bridge site are obtained.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446;U448.25

【相似文献】