Motion of adhering droplets induced by overlapping of gravitational and periodical acceleration
Motion of adhering droplets induced by overlapping of gravitational and periodical acceleration
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DOI：
10.1016/j.ijmultiphaseflow.2020.103537
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发表时间：
2021-02-01
影响因子：
3.8
通讯作者：
Janoske, U.
中科院分区：
文献类型：
--
作者：
Barwari, B.;Rohde, M.;Janoske, U.
这项实验工作研究了附着水滴在重力和谐波表面振动影响下的运动行为。使用两种具有适中静态接触角（74°-105°）的不同基材，并在垂直和水平方向分别施加表面振动。实验包括不同的液滴体积 (3-20 μl) 和不同的板倾角 (0 度 - 30 度)，适用于各种频率 (20-250 Hz) 和加速度 (5-300 m/s(2))。根据工艺参数的不同，液滴表现出不同的运动模式：静态振荡、横向运动和分离。不同的状态可以清楚地分开并在运动图中进行说明。分析表明，随着加速度的增加，液滴表现出混沌轮廓变形。人们发现，根据频率，液滴要么开始移动，要么随着幅度的增加而分解成更小的液滴。后一种称为分离模式。特别是，由于明显且特征化的轮廓变形，横向运动模式主要发生在液滴的第一固有频率范围内。关于液滴运动，通过无量纲经验方法找到稳定性极限，即启动液滴运动的阈值。 (C) 2020 Elsevier Ltd. 保留所有权利。
This experimental work deals with the motion behavior of adhering water droplets under the influence of gravity and harmonic surface vibration. Two different substrates with moderate static contact angles (74 degrees-105 degrees) are used and surface vibration is applied separately in vertical and horizontal directions. The experiments comprise different droplet volumes (3-20 mu l) and various plate inclinations (0 degrees-30 degrees) for a wide range of frequencies (20-250 Hz) and accelerations (5-300 m/s(2)). Depending on the process parameters, the droplet shows different motion patterns: static oscillation, transversal motion and separation. The different regimes can be clearly segregated and are illustrated in motion maps. The analysis reveals that with increasing acceleration the droplet exhibits a chaotic contour deformation. It was found that depending on the frequency the droplet either starts to move or is decomposed in smaller droplets with increasing amplitude. The later one is called separation mode. Especially the transversal motion mode takes place predominantly in the range of the first natural frequency of the droplet due to the pronounced and characterized asymmetric contour deformation. Concerning droplet motion a stability limit, i.e. a threshold value for initiating droplet motion is found by a dimensionless empirical approach. (C) 2020 Elsevier Ltd. All rights reserved.