基于数值模拟下π型断面气动选型

发布时间：2018-06-04 09:29

本文选题：风洞试验 + 数值模拟　；参考：《长安大学》2015年硕士论文

【摘要】：随着我国桥梁建设的不断推进,越来越多的大跨径桥梁以城市地标的身份出现在人们面前,在其建设过程中也出现了各种各样未知的难题需要桥梁建设者们去研究解决,特别是桥梁建设或运营期间所出现的风致振动现象,已逐渐成为大跨度桥梁建设的决定性因素。当前,桥梁工程师主要通过风洞试验来解决桥梁在实际风场中的抗风性能等相关问题,然而,风洞试验具有周期长、费用高、基础设备要求苛刻等一些客观因素,特别是在先期风洞试验结果不理想情况下所进行的重复试验,费时费力。随着计算流体力学的发展,数值风洞作为一种全新的研究手段,逐渐被科研工作者应用于桥梁抗风性能研究等相关领域。本文在与风洞试验对比的基础上,提出装配式的主梁断面组合设计形式,用于数值模拟下的气动断面选型,无论其单独应用抑或指导后期风洞试验,均具有重要意义。本文以某π型主梁断面斜拉桥为背景,在分别进行主梁节段模型测力、测振风洞试验的基础上,选取三种气动措施进行主梁装配组合,通过数值模拟对比主梁静三分力系数,主梁断面尾流特性分析,及二维断面颤振临界风速值等,在无需计算桥梁动力特性的前提下进行断面气动选型,选取方案可用于解决风洞试验过程中可能出现的桥梁风致振动现象,对最终主梁断面形式的确定具有十分重要的指导意义。经模拟,其结论与风洞试验结果一致。此外,研究发现数值模拟可用于分析不同气动措施下对绕流特性的改变,对于各气动措施尺寸的确定亦可达到预期效果,本文方法可用于指导π型断面气动选型设计。
[Abstract]:With the continuous development of bridge construction in our country, more and more long-span bridges appear in front of people as city landmarks. In the process of construction, a variety of unknown problems need to be studied and solved by bridge builders. Especially the wind-induced vibration phenomenon in the period of bridge construction or operation has gradually become a decisive factor in the construction of long-span bridges. At present, bridge engineers mainly use wind tunnel test to solve the wind resistance performance of bridge in actual wind field. However, wind tunnel test has some objective factors, such as long period, high cost, demanding foundation equipment and so on. In particular, repeated tests are time-consuming and laborious when the results of advanced wind tunnel tests are not satisfactory. With the development of computational fluid dynamics, numerical wind tunnel, as a new research method, has been gradually applied to bridge wind resistance research and other related fields. On the basis of comparison with wind tunnel test, this paper puts forward the assembled main beam cross section combination design form, which can be used in the selection of aerodynamic section under numerical simulation, no matter whether it is used alone or to guide the later wind tunnel test, it is of great significance. In this paper, taking a 蟺 type girder section cable-stayed bridge as the background, on the basis of the model force measurement and vibration measurement wind tunnel test of the main girder segment, three kinds of pneumatic measures are selected to assemble the main girder, and the static force coefficients of the main girder are compared by numerical simulation. Based on the analysis of the wake characteristics of the main beam section and the critical flutter wind velocity of the two-dimensional section, the aerodynamic selection of the cross-section is carried out without the need to calculate the dynamic characteristics of the bridge. The selected scheme can be used to solve the wind-induced vibration of bridges during the wind tunnel test, and it is of great significance to determine the final section form of the main beam. The simulation results show that the results are consistent with those of wind tunnel test. In addition, it is found that the numerical simulation can be used to analyze the change of flow characteristics under different aerodynamic measures, and the determination of the size of each pneumatic measure can achieve the expected effect. The method in this paper can be used to guide the design of 蟺 type aerodynamic section.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442

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