Viscous Droplet Impact on Nonwettable Textured Surfaces

Langmuir ◽  
2019 ◽  
Vol 35 (33) ◽  
pp. 10752-10761 ◽  
Author(s):  
Mehran Abolghasemibizaki ◽  
Neda Dilmaghani ◽  
Reza Mohammadi ◽  
Carlos E. Castano
Author(s):  
Kevin M. Beussman ◽  
Yechun Wang

The dynamics of viscous droplets near solid surfaces, especially micro-textured surfaces, and the interaction between them are of great importance in industrial applications, biochemical processes, and fundamental materials research on surface wettability. In this work, a three-dimensional spectral boundary element method has been employed to investigate the dynamics of a viscous droplet falling under gravity influence to micro-textured solid surfaces. The droplet size, in this study, is comparable to the size of the surface texture. The influences of the Bond number, relative size of the droplet with respect to the surface features, and the topological characteristics of the substrate on the droplet motion and deformation are investigated. The stress exerted on the substrate due to droplet motion is also explored.


Author(s):  
Hua Tan

In this paper, the investigation on dynamics of high-speed micron-sized droplet impact on textured surfaces is carried out through computational fluid dynamics (CFD) simulations. An open-source code Gerris has been adapted to address the challenging issues facing simulations of high-speed impact of microdroplets on the rough surface, such as thin spreading lamella, secondary droplet breakup, and small features of rough surfaces. Validation is first presented to evaluate the accuracy of the simulation code for modeling high-speed droplet impact on the microstructured surface. Then, we carry out 3D simulations of a 10 μm diameter water droplet impact on different textured surfaces with different impact velocities. We find that a large portion of the thin lamella actually surfs over the top of pillars during spreading with only center area of impact saturated with liquid. Our simulations indicate that both impact velocity and surface morphology play an important role in the splashing phenomenon. Increasing pillar spacing makes droplet impact more prone to splashing. Splashing on surfaces of larger pillar spacing is characterized by the breakup of high-speed jets. Larger impact velocity results in more intensified splashing. For a given impact velocity, densely packed pillars (i.e., smaller pillar spacing) can reduce or even suppress the splashing due to viscous drag effect from pillars in wetted region. The existing splashing threshold models that depend only on surface roughness fail in the prediction of the critical speed for splashing on textured surfaces.


2012 ◽  
Vol 100 (11) ◽  
pp. 111601 ◽  
Author(s):  
Azar Alizadeh ◽  
Vaibhav Bahadur ◽  
Sheng Zhong ◽  
Wen Shang ◽  
Ri Li ◽  
...  

2012 ◽  
Vol 17 (1) ◽  
pp. 14-19
Author(s):  
Jae-Bong Lee ◽  
Joo-Hyun Moon ◽  
Seong-Hyuk Lee

2006 ◽  
Vol 16 (8) ◽  
pp. 981-996 ◽  
Author(s):  
Richard A. Jepsen ◽  
Sam S. Yoon ◽  
Byron Demosthenous

2010 ◽  
Vol 20 (10) ◽  
pp. 909-922 ◽  
Author(s):  
Nikos Nikolopoulos ◽  
George Strotos ◽  
Konstantinos-Stephen P. Nikas ◽  
Manolis Gavaises ◽  
Andreas Theodorakakos ◽  
...  

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