Tandem droplet locomotion in a uniform electric field
Tandem droplet locomotion in a uniform electric field
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DOI：
10.1017/jfm.2022.875
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发表时间：
2022-07
影响因子：
3.7
通讯作者：
Chiara Sorgentone;Petia M. Vlahovska
中科院分区：
文献类型：
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作者：
Chiara Sorgentone;Petia M. Vlahovska
摘要 均匀电场中孤立的电中性液滴不会受到净力。然而，一对液滴可以响应场引起的偶极和流体动力相互作用而移动。如果液滴相同，则这对液滴的质心保持固定。在这里，我们表明，如果液滴具有不同的属性，则由于非互易的电流体动力学相互作用，这对液滴会经历净运动。我们使用渐进理论分析三维液滴轨迹，假设球形液滴和大间距，并基于边界积分方法进行数值模拟。根据液滴中心线相对于施加场方向的初始方向，动力学可能非常复杂。液滴倾向于朝着中心线平行或垂直于所施加的场方向的配置迁移，同时接触或无限期地分离。我们阐明了这些不同交互场景发生的条件。有趣的是，我们发现在某些情况下，液滴可以形成一对（串联），平行或垂直于施加的场方向平移。
Abstract An isolated charge-neutral droplet in a uniform electric field experiences no net force. However, a droplet pair can move in response to field-induced dipolar and hydrodynamic interactions. If the droplets are identical, the centre of mass of the pair remains fixed. Here, we show that if the droplets have different properties, the pair experiences a net motion due to non-reciprocal electrohydrodynamic interactions. We analyse the three-dimensional droplet trajectories using asymptotic theory, assuming spherical droplets and large separations, and numerical simulations based on a boundary integral method. The dynamics can be quite intricate depending on the initial orientation of the droplets line-of-centres relative to the applied field direction. Drops tend to migrate towards a configuration with line-of-centres either parallel or perpendicular to the applied field direction, while either coming into contact or indefinitely separating. We elucidate the conditions under which these different interaction scenarios take place. Intriguingly, we find that in some cases droplets can form a pair (tandem) that translates either parallel or perpendicular to the applied field direction.