单向水流作用下近壁管道横向涡激振动实验研究

Experimental study on vortex-induced vibrations of a pipeline near a plane boundary in steady flow

对单向水流作用下近壁管道横向涡激振动进行了实验模拟,重点探讨了管道与壁面间隙比(e/D)对管道涡激振动幅值和涡激振动频率响应特性的影响规律。实验结果表明,管道与壁面间隙宽度对管道涡激振动特性有较明显影响。在较大间隙比(e/D>0.66)下,管道振幅随着Vr数的增大先快速增长到最大值,然后平缓下降;在振动初期(即Vr数较小时),管道振动频率变化基本符合Strouhal规律;在振动中后期(即Vr数较大时),管道振动频率变化不符合Strouhal规律,而在管道固有频率附近缓慢增长。在较小间隙比(e/D<0.30)下,管道振幅随Vr数的增大先平缓上升到最大值,随后较快速下降;在振动初期,管道振动频率变化不遵循Strouhal规律;在整个振动范围内,与较大间隙比情况相比,随着Vr数增加,管道振动频率增长幅度明显较大。

Vortex-induced vibrations of a pipe near a plane boundary in steady flow were simulated experimentally. The influence of gap-diameter ratio （e/D） on the amplitude and frequency responses of the pipe＇s vibration is investigated. The experimental results show that the proximity of pipe to boundary has much influence upon the dynamic responses of the pipe. For the case of large e/D （ 0, 66）, with the increase of Vr number, the amplitude of pipe vibration increases quickly to a maximum value firstly, then decreases slowly; at the initial stage of vibration with small Vr number, the frequency of pipe vibration almost follows Strouhal＇s law, while it deviates obviously from Strouhal＇s law at the middle and last stage with big Vr number, which varies near its natural frequency. For the case of small e/D （d0.30）, with the increase of Vr number, the amplitude of pipe vibration increases slowly to a maximum value firstly, then decreases quickly; at the initial stage of vibration with small Vr number, the frequency of pipe vibration deviates obviously from Strouhal＇s law; at the whole range of vibration, with the increase of Vr number, the increasing amplitude of the frequency of pipe vibration is clearly larger than that in the case of large e/D.