Acoustic waves for active reduction of droplet impact contact time

Hosseini Biroun, Seyedmehdi, Li, Jie, Tao, Ran, Rahmati, Mohammad, McHale, Glen, Dong, Linxi, Jangi, Mehdi, Torun, Hamd and Fu, Richard (2020) Acoustic waves for active reduction of droplet impact contact time. Physical Review Applied, 14 (2). 024029. ISSN 2331-7019

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Minimizing droplet impact contact time is critical for applications such as self-cleaning, antierosion or anti-icing. Recent studies have used the texturing of surfaces to split droplets during impact or inducing asymmetric spreading, but these require specifically designed substrates that cannot be easily reconfigured. A key challenge is to realize an effective reduction in contact time during droplet impingement on a smooth surface without texturing but with active and programmable control. Our experimental results show that surface acoustic waves (SAWs), generated at a location distant from a point of droplet impact, can be used to minimize contact time by as much as 35% without requiring a textured surface. Additionally, the ability to switch on and off the SAWs means that a reduction in droplet impact contact time on a surface can be controlled in a programmable manner. Moreover, our results show that, by applying acoustic waves, the impact regime of the droplet on the solid surface can be changed from deposition or partial rebound to complete rebound. To study the dynamics of droplet impact, we develop a numerical model for multiphase flow and simulate different droplet impingement scenarios. Numerical results reveal that the acoustic waves can be used to modify and control the internal velocity fields inside the droplet. By breaking the symmetry of the internal recirculation patterns inside the droplet, the kinetic energy recovered from interfacial energy during the retraction process is increased, and the droplet can be fully separated from the surface with a much shorter contact time. Our work opens up opportunities to use SAW devices to minimize the contact time, change the droplet impact regime, and program or control the droplet’s rebounding on smooth or planar and curved surfaces, as well as rough or textured surfaces.

Item Type: Article
Subjects: F300 Physics
G100 Mathematics
H800 Chemical, Process and Energy Engineering
H900 Others in Engineering
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 07 Jul 2020 12:50
Last Modified: 31 Jul 2021 12:49

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