Journal ArticleDOI
Effect of geometrical parameters on rebound of impacting droplets on leaky superhydrophobic meshes
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TLDR
This study has studied the effect of different geometrical parameters of superhydrophobic copper meshes on different modes of droplet rebound, and observes that for flexible meshes, the transition to pancake type bouncing is induced at lower Weber numbers.Abstract:
When a droplet impacts a superhydrophobic sieve, a part of the droplet penetrates through it when the dynamic pressure (ρU2) of the impinging droplet exceeds the breakthrough pressure (γΓ/A). At higher impact velocities, the ejected-jet breaks and separates from the main droplet. The remaining part of the droplet bounces off the surface showing different modes (normal bouncing as a vertically elongated drop or pancake bouncing). In this work, we have studied the effect of different geometrical parameters of superhydrophobic copper meshes on different modes of droplet rebound. We observe three different effects in our study. Firstly, we observe pancake like bouncing, which is attributed to the capillary energy of the rebounding interface formed after the breaking of the ejected-jet. Secondly, we observe leakage of the droplet volume and kinetic energy due to the breaking of the ejected-jet, which leads to reduction in the contact times. Finally, we observe that for flexible meshes, the transition to pancake type bouncing is induced at lower Weber numbers. Flexibility also leads to a reduction in the volume loss from the ejected-jet. This study will be helpful in the design of superhydrophobic meshes for use under impact scenarios.read more
Citations
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Biotemplated hierarchical surfaces and the role of dual length scales on the repellency of impacting droplets
Matthew McCarthy,Konstantinos Gerasopoulos,Ryan Enright,James N. Culver,Reza Ghodssi,Evelyn N. Wang +5 more
TL;DR: In this article, the role of each length scale during droplet impact was investigated by decomposing the micro and nanoscale components of hierarchical superhydrophobic surfaces using the Tobacco mosaic virus and found that 10 µl water droplets rebounded at impact velocities greater than 4.3 µm/s.
Journal ArticleDOI
The Effect of Surface Roughness on the Contact Line and Splashing Dynamics of Impacting Droplets.
TL;DR: It is found that this maximum dynamic contact angle, together with the liquid properties, the ratio of the peak to peak roughness and the surface feature mean width, determines the splashing to no-splashing threshold.
Journal ArticleDOI
Droplet impact dynamics on textiles
Gannian Zhang,Miguel A. Quetzeri-Santiago,Corinne A. Stone,Lorenzo Botto,J. Rafael Castrejón-Pita +4 more
TL;DR: It is shown by balancing the dynamic impact and capillary pressures that the penetration behaviour is governed by a threshold pore size, the liquid characteristics and the droplet diameter, and the ability of a textile to repel water is controlled by the mesh size.
Journal ArticleDOI
Drop impact printing.
Chandantaru Dey Modak,Arvind Kumar,Arvind Kumar,Abinash Tripathy,Abinash Tripathy,Prosenjit Sen +5 more
TL;DR: In this article, the authors proposed a simple drop-on-demand printing technique which replaces the use of a nozzle with a sieve, enabling printing of nanoparticle suspension with 71% mass-loading, performed for surface tension range of 72-32mNm-1 and viscosity up to 33mPas.
Journal ArticleDOI
Droplet fragmentation using a mesh
TL;DR: In this paper, the atomization of droplets impacting a mesh, starting with the elementary unit of a single hole, is investigated, and it is shown how this process can be used to generate finely controlled sprays with micrometric droplet sizes and low kinetic energy, as is critical for agricultural applications.
References
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Hygro-responsive membranes for effective oil–water separation
TL;DR: The authors' membranes with hygro-responsive surfaces can separate, for the first time, a range of different oil-water mixtures in a single-unit operation, with >99.9% separation efficiency, by using the difference in capillary forces acting on the two phases.
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Design of ice-free nanostructured surfaces based on repulsion of impacting water droplets.
Lidiya Mishchenko,Benjamin Hatton,Vaibhav Bahadur,J. Ashley Taylor,Tom Krupenkin,Joanna Aizenberg +5 more
TL;DR: Factors contributing to droplet retraction, pinning and freezing are addressed by combining classical nucleation theory with heat transfer and wetting dynamics, forming the foundation for the development of rationally designed ice-preventive materials.
Journal ArticleDOI
Drop Impact on a Solid Surface
TL;DR: In this article, the authors focus on recent experimental and theoretical studies, which aim at unraveling the underlying physics, characterized by the delicate interplay of liquid inertia, viscosity, and surface tension, but also the surrounding gas.
Journal ArticleDOI
Contact time of a bouncing drop
TL;DR: This work measures how long the drop remains in contact with the solid during the shock to help quantify the efficiency of water-repellent surfaces (super-hydrophobic solids) and to improve water-cooling of hot solids, which is limited by the rebounding of drops as well as by temperature effects.
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Maximal deformation of an impacting drop
TL;DR: In this article, the impact of a liquid drop of low viscosity on a super-hydrophobic surface was studied. But the authors focused on the effect of the drop on the spread of the liquid on the surface.