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基于大比例节段模型风洞试验和计算流体动力学(CFD)方法,开展了港珠澳大桥青州航道桥大悬臂箱梁涡激共振抑振措施及机理的研究。通过风洞试验确定了边防撞栏是诱发竖弯涡振的原因,并开展CFD数值模拟,明确了边防撞栏和路缘石之间的距离不足以使其间的流速加快,两者之后是近似的死水区,形成连续的漩涡脱落现象,主导涡激共振的发生。设计了3种形式的风嘴结构(梯形风嘴、翼形风嘴与小翼形风嘴)以加快边防撞栏与路缘石之间的流速,避免其后形成连续的漩涡脱落现象。研究结果表明:风洞试验时,3种气动措施均可以在不同程度上抑制主梁竖弯涡振;CFD数值模拟及桥面风速测量均表明,各测点风速较原型断面有一定程度提高,卓越频率处的能量衰减较大,风嘴对边防撞栏后的流速起到了加速作用。
Based on the large scale section wind tunnel test and computational fluid dynamics (CFD) method, the Vibration Resonance Vibration Suppression Measures and Mechanism of Large Cantilever Box Girder of Qingzhou Channel Bridge on Hong Kong-Zhuhai-Macao Bridge was studied. Through the wind tunnel test, it is confirmed that the side crash barrier is the cause of vertical vortices induced, and CFD numerical simulation is carried out to make it clear that the distance between the side crash barriers and curbs is not enough to speed up the flow between them. Approximate dead zone, the formation of continuous vortex shedding phenomenon, the dominant vortex induced resonance. Three types of tuyere structures (trapezoidal tuyere, wing tuyere and small wing tuyere) are designed to speed up the flow between the barrier and the curb and avoid the subsequent vortex shedding. The results show that the three kinds of aerodynamic measures can restrain the vertical and horizontal vortices of the main girder to varying degrees in the wind tunnel test. The CFD numerical simulation and the wind speed measurement of the bridge deck show that the wind speeds at each measuring point are higher than the prototype section, The energy attenuation at the superior frequency is larger, and the velocity of the nozzle on the side after the crash barrier has accelerated.