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Investigation of Withinduced Vibration Control and Deterioration Counterrneasum for Stay-cables based on the Mechanisms of Aerodynamic Vthrations

基于气动振动机理的斜拉索诱发振动控制及劣化对策研究

基本信息

批准号：
18360218
负责人：
MATSUMOTO Masaru
金额：
$ 9.78万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

The objectives of this study are to discuss mechanisms of aerodynamic instabilities of stay-cables based on intensities of Karman vortex and to investigate the control methods and additional damping for mitigating the aerodynamic vibration. The obtained information in this study must be useful to consider the countenneasuresibr stay-cable deterioration.In this study, all the factors for the aerodynamic instabilities of stay-cables, which are axial flow in the wake of inclined cable, water rivulet formed on the upper surface of the cable, critical Reynolds number effects and so on, are discussed as the effects of reduction of Karman vortex. For example, when the axial flow is weak in the wake of inclined cable, the intensity of Karman vortex increases and also, if the axial flow is intensive, the Karman vortex intensity becomes small. Then, it becomes clear that if the axial flow is unsteady, which means the Karman vortex intensity is also unsteady, unsteady galloping may occur. Also, the position of water rivulet controls the intensity of Karman vortex, and then, the aerodynamic instability occurs at the certain rivulet position. Therefore, the both rain-wind induced vibration and dry-state galloping must be generated by the combination of the above mentioned factors, and these mechanisms are explained by the reduction of Karman vortex.The effects of Scruton number, which is a mass-damping parameter, on the galloping instability are sensitive to the galloping due to the critical Reynolds number, but less sensitive to the galloping generated by the axial flow. Furthermore, more field observation data of the dry-state galloping of the real stay-cables must be needed.

本研究的目的是讨论基于卡门涡强度的拉索气动不稳定性的机制，并研究减轻气动振动的控制方法和附加阻尼。本研究中获得的信息对于考虑斜拉索恶化的预防措施必定有用。在本研究中，斜拉索尾流中的轴向流、拉索上表面形成的水流、临界雷诺数效应等所有导致斜拉索气动失稳的因素都被讨论为卡门涡流减少的影响。例如，当斜缆尾流的轴流较弱时，卡门涡流的强度增大；同样，如果轴流较强，则卡门涡流的强度变小。由此可见，如果轴流不稳定，即卡门涡流强度也不稳定，则可能会发生非定常舞动。另外，水流的位置控制着卡门涡的强度，从而在一定的水流位置处会出现气动失稳。因此，雨风激振和干态舞动必定是由上述因素共同产生的，而这些机制可以通过卡门涡旋的减弱来解释。作为质量阻尼参数的斯克鲁顿数对舞动失稳的影响，由于临界雷诺数而对舞动不敏感，而对轴流产生的舞动不太敏感。此外，还需要更多真实斜拉索干态驰骋的现场观测数据。