Electrowetting of a leaky dielectric droplet under a time-periodic electric field
Electrowetting of a leaky dielectric droplet under a time-periodic electric field
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DOI：
10.1103/physrevfluids.6.073701
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发表时间：
2021-07-02
影响因子：
2.7
通讯作者：
Narayanan, Ranga
中科院分区：
文献类型：
--
作者：
Pillai, Dipin S.;Sahu, Kirti Chandra;Narayanan, Ranga
研究了垂直方向交变静电场作用下，泄漏介质固着液滴的润湿和接触线动力学。建立了一个基于前驱膜的加权剩余积分边界层降阶模型。还考虑了理想导电液滴和理想介电液滴的极限情况。结果表明，液滴振荡频率的两倍，由于二次依赖的麦克斯韦应力上施加的交流电场的强制电位。这些振荡发生在一个平衡的配置，这可以实现一个恒定的（直流）电位相当于均方根电位的交流电场。它还表明，接触线运动的交流电强迫的振幅单调增加。交流电场的显著增加导致尖峰和顶部电极处的界面破裂。取决于静态接触角，液滴变形可以成为非单调的交流电场的施加频率增加。这种行为归因于受液滴润湿性影响的强制时间尺度和响应时间尺度之间的竞争。电导率比，介电常数比，和不同波形的交流强迫的作用也进行了研究。
The wetting and contact line dynamics of a leaky dielectric sessile droplet under an alternating (ac) electrostatic field applied in the vertical direction is investigated. A thin precursor film-based reduced-order model using the weighted residual integral boundary layer technique is developed. The limiting cases of perfect conducting and perfect dielectric droplets are also considered. It is shown that the droplet oscillates with a frequency twice that of the forcing potential due to the quadratic dependence of the Maxwell stress on the applied ac electric field. These oscillations take place about an equilibrium configuration, which can be achieved with a constant (dc) electric potential equivalent to the root-mean-square potential of the applied ac field. It is also shown that the contact line motion increases monotonically with the amplitude of the ac electric forcing. A significant increase in ac field leads to spiking and the interface ruptures at the top electrode. Depending on the static contact angle, the droplet deformation can become nonmonotonic as the applied frequency of the ac electric field increases. This behavior is attributed to the competition between the timescale of forcing and the timescale of the response as affected by the drop's wettability. The role of conductivity ratio, permittivity ratio, and different waveforms of ac forcing are also investigated.