悬跨管道间隙比对涡激振动动态响应的影响

Influence of Gap Ratio on Vortex-Induced Vibration Dynamic Response of Free Spanning Pipeline

摘要: 为了理清管道悬跨间隙比对涡激振动动态响应的影响，采用数值仿真方法分析了悬跨管道间隙比、海流速度对漩涡脱落频率、涡激振动动态响应的影响。结果表明：间隙比 < 2时，升力系数振幅中心位置是一负值；间隙比 > 4时，升力系数振幅中心位置接近0，对周围流场的影响消失。同一间隙比下，升力系数频率随海流速度呈线性变化；不同间隙比下，悬跨管道漩涡脱落频率随约化速度呈线性变化。不同间隙比悬跨管道涡激振动频率锁定时的海流速度相等，锁定后，横向(Z方向)振幅随着间隙比的增大逐渐增大，间隙比达到4后，影响消失。不同间隙比悬跨管道涡激振动一阶模态自振频率锁定时的约化速度相差不大，在(5,7)范围内；间隙比小于2时，对横向(Z方向)振动中心位置的影响非常明显，间隙比达到4后，横向(Z方向)振动中心位置逐渐趋向于0。

Abstract: In order to clarify the influence of free span gap ratio on vortex-induced vibration (VIV) dynamic response, the effects of free span gap ratio and current velocity on vortex shedding frequency and VIV dynamic response were analyzed by numerical simulation method. The results show that the center of lift coefficient amplitude is a negative value when the clearance ratio is <2, and the center of lift coefficient amplitude is close to 0 when the clearance ratio is >4. The frequency of lift coefficient varies linearly with a current velocity at the same gap ratio, and the frequency of vortex shedding varies linearly with a reduced velocity at different gap ratios. When the vortex-induced vibration frequency is locked, the velocity of ocean current is equal. After locking, the transverse (Z direction) amplitude increases with the increasing of the gap ratio, and the influence disappears when the gap ratio reaches 4. When the gap ratio is less than 2, the reduction velocity of vortex-induced vibration in the first-order mode of free vibration is similar, and the influence of the gap ratio on the location of the vibration center in the transverse (Z direction) is obvious, when the gap ratio reaches 4, the center of transverse (Z direction) vibration tends to 0.