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为研究紊流积分尺度对桥梁颤振导数的影响,选取了理想平板、流线型箱梁以及高宽比1∶6矩形断面三种气动外形渐变的典型断面,采用主动格栅模拟了二维大积分尺度紊流场,利用强迫振动装置测试了主动格栅紊流场中三种断面节段模型的颤振导数,并与均匀流场试验值进行了对比。试验结果表明,紊流积分尺度对颤振导数的影响随断面钝化逐渐减弱;主动格栅二维紊流对流线型断面颤振导数影响较小,无明显趋势性变化;对钝体矩形断面影响显著,并且随折减风速增加而加剧,其气动阻尼项导数由正向负衰减显著,有利于改善结构颤振性能。
In order to study the influence of turbulence integral scale on the flutter derivative of bridge, three typical sections with aerodynamic shape gradients of ideal slab, streamlined box girder and aspect ratio 1: 6 rectangular section are selected. The active quadratic Scale turbulent flow field, the flutter derivatives of the three section models in active grid turbulence field were tested by forced vibration device and compared with the uniform flow field test data. The experimental results show that the influence of turbulence integral scale on the flutter derivative decreases gradually with the passivation of the cross section. The two-dimensional turbulent convection cross-section flutter derivative has little effect on the active grid, and has no obvious trend change. Significant, and aggravate with decreasing wind speed. The derivative of the aerodynamic damping leads to a significant positive attenuation, which helps to improve the structural flutter performance.