并列双钝体箱梁间距对涡激共振特性的影响

INFLUENCE OF SPACE ON VORTEX-INDUCED VIBRATION CHARACTERISTICS OF TWIN PARALLEL BLUFF-BOX GIRDERS

首先通过节段模型风洞试验测试了并列双幅钝体箱梁在10个不同间距(双幅箱梁的净间距D与单幅箱梁宽B之比D/B的变化范围为0.2~4.0)时的涡激共振振幅与风速锁定区间,并与单幅钝体箱梁的的涡激共振振幅与风速锁定区间进行了对比,研究了对并列双幅钝体箱梁的间距对涡激共振特性的影响。然后基于CFD数值计算结果,从流场的角度对涡激共振特性的影响机理进行了分析。研究结果表明:下游箱梁对上游箱梁涡激共振的影响在0.2≤D/B≤2.0时表现为一定的放大效应,在D/B≥2.5时基本可以忽略;上游箱梁对下游箱梁涡激共振的影响表现为明显的放大效应,这种放大效应在D/B=0.8时最显著,即使当D/B=4.0时仍不可忽略。

The wind tunnel tests of sectional models for twin parallel bluff-box girders were performed firstly.Vortex-induced vibration amplitude and wind velocity locking region of twin parallel box girders in 10 different spaces were investigated and compared with those of single box girders.The space ratio of D/B is from 0.2 to 4.0,where D is net space between twin box girders and B is width of a single box girder.Then the influencing mechanism of vortex-induced vibration was studied based on flow fields attained from CFD numerical calculation.The study results show that the influence of a leeward box girder on the vortex-induced vibration of a forward box girder is shown as an amplification effect when 0.2≤D/B≤2.0 and can be ignored when D/B≥2.5.The influence of a forward box girder on the vortex-induced vibration of a leeward box girder is shown as a notably amplification effect.The amplification effect is the most significant when D/B=0.8 and cannot be neglected even when D/B=4.0.