Free surface lubrication of rotating cylinders by Newtonian liquid jets was investigated at different impingement positions, jet- and circumferential velocities. The interaction between impinging round laminar jet and rotating surface was characterised by high-speed imaging. Compared to flat surface impingement, the liquid deposition mechanism is more complex and often accompanied by phenomena such as splashing, jet deflection and formation of radial surface stripes. Liquid splashing initially develops in direct deposition regime due to hydraulic jump-induced droplet shedding, transitioning to lamella instability splash at higher Reynolds numbers. The critical Reynolds number for splash onset is of same order of magnitude as for flat surface impingement and fairly constant at low relative jet impingement angles, but increases exponentially when angle approaches 90°. Liquid film width and thickness were both determined proportional to the square root of the jet/surface velocity ratio, with respective power law models in good agreement with measured values.

中文翻译：

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冲击牛顿液体射流对旋转圆柱体的自由表面润滑

在不同的冲击位置、射流和圆周速度下研究了牛顿液体射流对旋转圆柱体的自由表面润滑。高速成像表征了撞击圆形层流射流与旋转表面之间的相互作用。与平面撞击相比，液体沉积机理更为复杂，且常伴有飞溅、射流偏转和径向表面条纹形成等现象。由于水跃引起的液滴脱落，液体飞溅最初在直接沉积状态下发展，在较高雷诺数下转变为薄片不稳定飞溅。飞溅开始的临界雷诺数与平面撞击的数量级相同，并且在较低的相对射流撞击角度下相当恒定，但当角度接近 90° 时呈指数增长。液膜宽度和厚度均与射流/表面速度比的平方根成正比，各自的幂律模型与测量值非常吻合。