Oscillation characteristics of micro-droplets, when in partial contact with a dry and homogeneous substrate, are investigated using a volume of fluid (VOF) numerical method. Water is used as a fluid in both numerical and experimental studies. The velocity vectors are plotted along the phase boundary line, i.e. along the droplet interface, to show how the contact angle impacts the droplet shape during the entire oscillation process. It has been predicted that when the surface/liquid combination is of larger contact angle, the water droplet tends to spread partially as the contact velocity dynamics dominate over inertia, thereby restricting the change in shape, i.e. resulting in lesser mode of oscillations. However, all droplets that are considered here show a damped harmonic motion with the amplitude gradually decreasing to zero. Particularly, at a lower Weber number impact, it is predicted that both the height and spreading dynamics exhibit a unique decaying function for each droplet size considered.

中文翻译：

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低韦伯数撞击微液滴的振荡特性

使用流体体积 (VOF) 数值方法研究微液滴在与干燥且均匀的基材部分接触时的振荡特性。在数值和实验研究中，水被用作流体。速度矢量沿相边界线，即沿液滴界面绘制，以显示在整个振荡过程中接触角如何影响液滴形状。据预测，当表面/液体组合具有较大的接触角时，水滴趋于部分扩散，因为接触速度动力学超过惯性，从而限制了形状的变化，即导致较小的振荡模式。然而，这里考虑的所有液滴都显示出阻尼谐波运动，幅度逐渐减小到零。特别，