In this article, the instability and dynamic characteristics of fluid-conveying microtubes with surface roughness are studied. A theoretical model is presented to describe the dynamic behaviors of rough microtubes by introducing correction factors, which account for the effects of the surface roughness both on the structure and the internal fluid. The results demonstrate that the surface roughness has little effect on the correction factors for structure, but dramatically decreases the correction factors for fluid, which indicates that the Coriolis force and centripetal force caused by the internal fluid are reduced. For clamped–clamped microtubes, the surface roughness makes the nondimensional critical velocity for divergence and the natural frequency increase. And as the roughness height or the wave number increases, both the critical velocity and the frequency increase. For cantilevered microtubes, the critical velocity for fluttering depends on the surface roughness and the mass ratio. Curves describing the relationship between the nondimensional critical velocity \(\hat{U}_{\text{cr}}\) and the mass ratio \(\beta\) for smooth and rough microtubes are presented. Each curve contains a S-shaped segment, which is associated with the instability–restabilization–instability sequence. The surface roughness induces the curve shifting to the upper right of the \(\hat{U}_{\text{cr}}\) − \(\beta\) plane. In the region far away from the S-shaped segment, the critical velocity increases with the increasing of roughness height. And in the vicinity of S-shaped segment, the critical velocity for the rough microtube may be less than the value for the smooth microtube because of the sharply varying of critical velocity with mass ratio. The effects of surface roughness on the frequency of cantilevered microtubes are also analyzed and discussed.

本文研究了具有表面粗糙度的流体输送微管的不稳定性和动态特性。通过引入校正因子，提出了一个理论模型来描述粗糙微管的动态行为，这些因子考虑了表面粗糙度对结构和内部流体的影响。结果表明，表面粗糙度对结构修正系数的影响不大，但流体修正系数显着降低，表明内部流体引起的科里奥利力和向心力减小。对于夹钳微管，表面粗糙度使发散的无量纲临界速度和固有频率增加。并且随着粗糙度高度或波数的增加，临界速度和频率都增加。对于悬臂微管，颤振的临界速度取决于表面粗糙度和质量比。描述无量纲临界速度之间关系的曲线\(\hat{U}_{\text{cr}}\)和光滑和粗糙微管的质量比\(\beta\)。每条曲线都包含一个 S 形段，它与不稳定性-再稳定-不稳定性序列相关。表面粗糙度导致曲线移动到\(\hat{U}_{\text{cr}}\)  −  \(\beta\)飞机。在远离 S 形段的区域，临界速度随着粗糙度高度的增加而增加。而在S形段附近，由于临界速度随质量比的急剧变化，粗糙微管的临界速度可能小于光滑微管的值。还分析和讨论了表面粗糙度对悬臂微管频率的影响。