典型断面涡激振动与涡激力展向相关性研究
发布时间：2019-01-18 21:49
【摘要】：大跨度桥梁具有多阶固有振动模态，在不同的来流风速下，各阶模态可能依次发生涡激共振。因此，研究柔性结构各阶模态涡振的起振风速和最大振幅具有重要意义。虽然针对某阶振动模态下的矩形及H形断面涡振性能已有很多研究，但最大涡振振幅随模态频率、质量阻尼参数、气动阻尼等的变化规律还不明确。Scruton数即质量阻尼参数是影响涡激振动的重要因素，Sc数会影响涡激振动锁定区间和涡振振幅，但Sc数中的质量参数和阻尼参数对涡激振动影响不同，缺乏质量参数和阻尼参数与涡振锁定区间、涡振振幅之间的关系。另外，在实际风作用下，沿桥轴线方向上的涡激力并不是完全相关的，特别是对于大跨桥梁，涡激力的空间相关性更加明显，涡激力展向相关性的研究对涡振振幅预测有重要意义。 基于以上几个问题，本文主要进行了如下几个方面的研究： (1)介绍了桥梁风致振动的主要类型，特别是对涡激振动研究现状做了概括，并对涡激振动的相关理论做了简要的阐述。 (2)对宽高比B/D=6的大小比例矩形断面及B/D=5的H形断面进行节段模型涡激振动试验。相同质量及阻尼比的同一模型在不同弹性悬挂频率下的试验结果表明，矩形与H形断面的竖向涡振振幅不随悬挂频率改变。 (3)分别研究了质量、阻尼参数对两类断面涡激共振的影响。结果表明，在相同质量下，两类断面的涡振振幅随结构阻尼比s的增加而显著减小；而在相同结构阻尼比s下，两类断面的最大竖向涡振振幅对质量参数的变化都不敏感。应用断面颤振导数分析了不同质量下的气动阻尼变化，在增加质量的同时实际上降低了气动模态阻尼比a，因而可能引起最大涡振振幅对质量变化不敏感。 (4)矩形断面风洞试验观测到的两个竖向涡振区间，其最大振幅比约2.2。分别计算了两个涡振区间内与最大振幅对应的气动阻尼，结果表明在考虑气动阻尼影响下应用简谐涡激力模型对最大振幅比进行分析，发现最大振幅比不与St2成反比是因为两个区间最大振幅处气动阻尼的差异。 (5)以矩形和H形断面风洞试验结果为基础，运用FLUENT对矩形和H形断面进行数值模拟，数值模拟结果和风洞试验结果吻合较好。 (6)通过圆柱体风洞试验，对涡激力展向相关性进行了分析，结果表明不同截面处90°位置的展向相关性比180°位置处的展向相关性大，，涡激力的展向相关性与振幅、雷诺数有关。
[Abstract]:There are many natural vibration modes in long-span bridges, and vortex-induced resonance may occur at different wind speeds. Therefore, it is of great significance to study the initial wind speed and maximum amplitude of vortex vibration of flexible structures. Although much research has been done on the vortex vibration performance of rectangular and H-shaped sections in a certain vibration mode, the maximum amplitude of vortex vibration depends on the modal frequency and mass damping parameters. The variation of aerodynamic damping is not clear. Scruton number, that is, mass damping parameter, is an important factor affecting vortex-induced vibration, and Sc number will affect the locking range and amplitude of vortex-induced vibration. However, the mass and damping parameters in Sc number have different effects on the vortex-induced vibration, and the relationship between the mass parameter and damping parameter and the locking interval and amplitude of vortex-induced vibration is absent. In addition, under the action of actual wind, the vortex-induced forces along the axis of the bridge are not completely related, especially for long-span bridges, the spatial correlation of vortex-induced forces is more obvious. The study of the spanned correlation of vortex-induced forces is of great significance in predicting the amplitude of vortex-induced vibration. Based on the above problems, this paper mainly studies the following aspects: (1) the main types of wind-induced vibration of bridges are introduced, especially the research status of vortex-induced vibration is summarized. The theory of vortex-induced vibration is briefly described. (2) the vortex-induced vibration tests of the rectangular section with the ratio of width to height (B/D=6) and the H-section of the B/D=5 are carried out. The experimental results of the same model with the same mass and damping ratio at different elastic suspension frequencies show that the amplitude of vertical vortex vibration of rectangular and H-shaped sections does not change with the suspension frequency. (3) the effects of mass and damping parameters on the vortex-induced resonance of two kinds of cross-sections are studied. The results show that under the same mass, the amplitude of vortex vibration of the two sections decreases significantly with the increase of the damping ratio of the structure, while the maximum vertical vibration amplitude of the two sections is not sensitive to the variation of the mass parameters at the same damping ratio of the structure. The variation of aerodynamic damping under different mass is analyzed by using cross-section flutter derivative, and the aerodynamic mode damping ratio a is actually reduced while increasing mass, which may cause the maximum amplitude of vortex vibration to be insensitive to mass change. (4) the maximum amplitude ratio of the two vertical vortex vibration regions observed by wind tunnel test with rectangular section is about 2.2. The aerodynamic damping corresponding to the maximum amplitude in two vortex-vibration regions is calculated respectively. The results show that the harmonic vortex-induced force model is used to analyze the maximum amplitude ratio under the influence of aerodynamic damping. It is found that the maximum amplitude ratio is not inversely proportional to St2 because of the difference of aerodynamic damping at the maximum amplitude of the two regions. (5) based on the experimental results of rectangular and H-section wind tunnels, the numerical simulation of rectangular and H-shaped sections is carried out by using FLUENT. The results of numerical simulation are in good agreement with those of wind tunnel tests. (6) through the cylindrical wind tunnel test, the spanwise correlation of vortex-induced forces is analyzed. The results show that the spanwise correlation at 90 掳at different cross-sections is greater than that at 180 掳, and the spanned correlation and amplitude of vortex-induced forces are higher than those at 180 掳. Reynolds number.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3
本文编号：2411163
[Abstract]:There are many natural vibration modes in long-span bridges, and vortex-induced resonance may occur at different wind speeds. Therefore, it is of great significance to study the initial wind speed and maximum amplitude of vortex vibration of flexible structures. Although much research has been done on the vortex vibration performance of rectangular and H-shaped sections in a certain vibration mode, the maximum amplitude of vortex vibration depends on the modal frequency and mass damping parameters. The variation of aerodynamic damping is not clear. Scruton number, that is, mass damping parameter, is an important factor affecting vortex-induced vibration, and Sc number will affect the locking range and amplitude of vortex-induced vibration. However, the mass and damping parameters in Sc number have different effects on the vortex-induced vibration, and the relationship between the mass parameter and damping parameter and the locking interval and amplitude of vortex-induced vibration is absent. In addition, under the action of actual wind, the vortex-induced forces along the axis of the bridge are not completely related, especially for long-span bridges, the spatial correlation of vortex-induced forces is more obvious. The study of the spanned correlation of vortex-induced forces is of great significance in predicting the amplitude of vortex-induced vibration. Based on the above problems, this paper mainly studies the following aspects: (1) the main types of wind-induced vibration of bridges are introduced, especially the research status of vortex-induced vibration is summarized. The theory of vortex-induced vibration is briefly described. (2) the vortex-induced vibration tests of the rectangular section with the ratio of width to height (B/D=6) and the H-section of the B/D=5 are carried out. The experimental results of the same model with the same mass and damping ratio at different elastic suspension frequencies show that the amplitude of vertical vortex vibration of rectangular and H-shaped sections does not change with the suspension frequency. (3) the effects of mass and damping parameters on the vortex-induced resonance of two kinds of cross-sections are studied. The results show that under the same mass, the amplitude of vortex vibration of the two sections decreases significantly with the increase of the damping ratio of the structure, while the maximum vertical vibration amplitude of the two sections is not sensitive to the variation of the mass parameters at the same damping ratio of the structure. The variation of aerodynamic damping under different mass is analyzed by using cross-section flutter derivative, and the aerodynamic mode damping ratio a is actually reduced while increasing mass, which may cause the maximum amplitude of vortex vibration to be insensitive to mass change. (4) the maximum amplitude ratio of the two vertical vortex vibration regions observed by wind tunnel test with rectangular section is about 2.2. The aerodynamic damping corresponding to the maximum amplitude in two vortex-vibration regions is calculated respectively. The results show that the harmonic vortex-induced force model is used to analyze the maximum amplitude ratio under the influence of aerodynamic damping. It is found that the maximum amplitude ratio is not inversely proportional to St2 because of the difference of aerodynamic damping at the maximum amplitude of the two regions. (5) based on the experimental results of rectangular and H-section wind tunnels, the numerical simulation of rectangular and H-shaped sections is carried out by using FLUENT. The results of numerical simulation are in good agreement with those of wind tunnel tests. (6) through the cylindrical wind tunnel test, the spanwise correlation of vortex-induced forces is analyzed. The results show that the spanwise correlation at 90 掳at different cross-sections is greater than that at 180 掳, and the spanned correlation and amplitude of vortex-induced forces are higher than those at 180 掳. Reynolds number.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3
【参考文献】
相关期刊论文 前7条
1 鲜荣;廖海黎;李明水;;大比例主梁节段模型涡激振动风洞试验分析[J];实验流体力学;2009年04期
2 曹丰产,项海帆;圆柱非定常绕流及涡致振动的数值计算[J];水动力学研究与进展(A辑);2001年01期
3 方平治;顾明;;高雷诺数条件下二维方柱涡激振动的数值模拟[J];同济大学学报(自然科学版);2008年02期
4 张伟;葛耀君;;H形断面桥梁风致振动的流场机理[J];土木工程学报;2009年05期
5 鲜荣;廖海黎;李明水;;大跨主梁沿跨向涡振Scanlan非线性模型应用[J];振动与冲击;2009年04期
6 周涛;朱乐东;郭震山;;经验非线性涡激力模型参数识别[J];振动与冲击;2011年03期
7 刘志文;周帅;陈政清;;宽高比为4的矩形断面涡激振动响应数值模拟[J];振动与冲击;2011年11期
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