Study to Clarify The Mechanism of Uniquely Large Horizontal Bridge Response Located in The Wake of aHill

研究阐明位于山尾的独特大型水平桥响应机制

• 批准号: 13650526
• 负责人: KIMURA Kichiro
• 金额: $ 2.24万
• 依托单位: Kyushu Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650526/
• 关键词: Wind-induced vibration; Buffeting; Wake; Fluctuating wind velocity; Isolated hill; Bridge under construction; Split-film probe; Wind tunnel experiment; 風速変動; 複雑地形; 可視化

This study was conducted to clarify the mechanism of uniquely large horizontal response observed with a bridge model located in the wake of an isolated hill.The bridge and hill models were simplified as a cantilever and a cone. The location of the bridge model in the wake of the hill and horizontal skew angle were varied and responses were measured. The diameter of the hill was 4.5H, taking H as the height. The length of the cantilever model was H and it was located at height of 0.123H. The horizontal response became large when the model when the model was located around 3.3H leeward from the hill center. Also the response became large when the cantilever model had wind skew angle of 40 degrees. The kurtosis of the response sometimes reached to 4 to 4.5. With a series of flow visualization experiment, the formation of conical vortices that has the axis with skew angle of 40 to 50 degrees was suggested, and these vortices were thought to be the possible cause of large horizontal response.Then the response and fluctuating wind velocity were measured simultaneously, and conditional sampling based on the occurrence of large responses was conducted to clarify the fluctuating wind velocity characteristics causing the large response. These were some cases where fluctuating wind velocity that acts on the bridge model with skew front line of around 40 degrees caused large responses, and that was considered to correspond to the vortex structure suggested in the flow visualization experiment.On the other hand, there were other cases where these fluctuating wind velocity characteristics were not observed, or reproduction of the experimental results was not good. The cause is now sought considering sensitive effects by flow condition etc. Also the aerodynamic force characteristics are to be measured using simultaneous pressure measurement experiment.

进行了这项研究是为了阐明在隔离山丘之后使用的桥模型观察到的独特大型水平响应的机制。桥和山坡模型被简化为悬臂和锥体。在山丘和水平偏斜角度之后，桥模型的位置变化并测量响应。山的直径为4.5h，将H视为高度。悬臂模型的长度为H，位于0.123H的高度。当模型位于山中心3.3小时大约3.3小时时，水平响应就变得很大。当悬臂模型的风向偏斜角为40度时，响应也变得很大。反应的峰度有时达到4至4.5。提出了一系列流动可视化实验，提出了具有偏斜角为40至50度的轴的圆锥形涡旋的形成，并认为这些涡旋被认为是对水平响应的较大响应的可能原因。大反应。在某些情况下，在40度左右的前线上起作用的风速波动，引起了巨大的响应，并且认为这与流动可视化实验中建议的涡流结构相对应。另一方面，在其他情况下，这些情况并未在这些情况下易变。现在，考虑通过流动条件等敏感效应等的原因等。此外，还应通过同时进行压力测量实验来测量空气动力的特性。