带风嘴π型组合梁断面涡振性能试验及抑振机理研究

Experimental study on vortex vibration performance and vibration suppression mechanism of π-shaped composite beams with wind fairing

为研究带风嘴π型叠合梁断面涡激振动性能,基于某在建斜拉桥工程的设计方案,通过1∶50缩尺比刚性节段模型自由悬挂风洞试验,测试了不同工况下π型梁的涡振性能,并对上、下稳定板及组合稳定板措施的抑振效果进行了研究。进一步采用SST k-ω湍流模型,模拟了原断面和推荐措施下π型梁断面周围的流场特性,并结合绕流涡量演化图探讨了涡振抑制机理。研究结果表明:原断面在5种风攻角状态下均发生明显竖向涡激振动,且+5°攻角竖向幅值超过规范允许振幅。设置与边主梁等高的下中央稳定板明显降低了涡激振动响应,主梁涡振性能随着下中央稳定板高度的增加先提升后降低。

In order to study vortex-induced vibration(VIV)performance ofπ-shaped composite beams with wind fairing,based on the design scheme of a cable-stayed bridge under construction,the VIV performance of the x-shaped beam under different working conditions was tested through a 1:50 scale rigid section model free suspension wind tunnel test.A study was conducted on the vibration suppression effect of upper and lower stabilizing plates and combined stabilizing plate measures.Furthermore,SST κ-ω turbulence model was used to simulate the flow field characteristics around the original section and the recommended measures of the π-shaped beam section,and the vortex suppression mechanism was explored in conjunction with the vortex evolution diagram of the surrounding flow.The research results indicate that the original cross-section undergoes significant vertical VIV under five different wind attack angles,and the vertical amplitude of the+5°attack angle exceeds the allowable amplitude in the specifications.The setting of a lower central stable plate at the same height as the edge main beam significantly reduces the vortex induced vibration response,the vortex vibration performance of the main beam first increases and then decreases with the increase of the height of the lower central stabilizing plate.