Periodic wavy patterns emerge and align in a transverse direction once a viscous fluid is coated onto a surface moving above a critical speed. In this study, we examine how this flow instability, which is usually referred to as ribbing, is triggered or damped on a moving topographic surface. To examine the transient flow behavior, the liquid first came into contact with a smooth surface, followed by a downstream surface with small-scale V-shaped grooves. Flow visualizations revealed a topography-induced flow stabilization and a matching of rib frequencies with the underlying groove patterns, depending on the groove geometry and capillary number.

中文翻译：

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涂在地形表面的牛顿流体的肋不稳定性

一旦将粘性流体涂覆到以高于临界速度移动的表面上，就会出现周期性的波浪形图案，并在横向上对齐。在这项研究中，我们研究了在流动的地形表面上如何触发或衰减这种流动不稳定性（通常称为肋）。为了检查瞬时流动行为，液体首先与光滑的表面接触，然后与带有小尺寸V形凹槽的下游表面接触。流动的可视化显示了地形引起的流动稳定，并且肋的频率与下面的沟槽图案相匹配，具体取决于沟槽的几何形状和毛细管数。