OUT-OF-PLANE VIBRATION OF CURVED PIPES DUE TO PULSATING FLUID FLOW

与直管动力学相比，输送流体的曲管动力学研究较少。特别是，控制输流柔性弯管运动的非线性积分-微分方程尚未在重力的影响下导出，并且没有与弯管的面外振动相关的实验结果。本文对脉动流体作用下弯管的面外振动进行了理论分析和实验研究。首先，计算了一维流的稳态流体速度对平面外振动的振型和固有频率的影响。其次，研究了流体脉动分量对静态平衡解稳定性的影响。第三，利用本文所导出的弯曲柔性管道空间非线性振动的非线性积分微分方程，对上述现象进行了讨论。最后，利用该图像处理系统测量了脉动流作用下弯管的空间运动。

The dynamics of curved pipes conveying fluid are not so much studied which is compared with the dynamics of the straight pipe. In particular, the nonlinear integro-differential equations governing motion of flexible curved pipe conveying fluid are not yet derived under the influence of gravity, and there are no experimental results associated with the out-of-plane vibration of a curved pipe. In this paper, out-of-plane vibration of a curved pipe due to the pulsating fluid flow, has been investigated analytically and experimentally. First, mode shape and natural frequency of out-of-plane vibration was calculated as a function of the steady-state fluid velocity of the one-dimensional flow. Second, the stabilities of its static equilibrium solution depending on the pulsating component of fluid flow were investigated. Third, the above phenomena were discussed using the nonlinear integro-differential equations governing the nonlinear spatial vibration of a flexible curved pipe which have been derived in this paper. Finally the spatial motions of a curved pipe due to the pulsating fluid flow were measured by using the image processing system.