Bouncing of an ellipsoidal drop on a superhydrophobic surface

Abstract

Drop impact on superhydrophobic surfaces has received significant attention because of the advantages of self-cleaning and anti-icing attained by minimum contact time with the surface. Drop hydrodynamics is generally assumed to be axisymmetric, and the contact time is still bounded below by a theoretical Rayleigh limit. In this study, we report an ellipsoidal drop impact on a superhydrophobic surface to demonstrate an efficient way to reduce the contact time and suppress the bounce magnitude by breaking the symmetry. The outcome of the bounce is characterized in terms of a geometric aspect ratio (AR) and Weber number of the drop by comparing the dynamics with a spherical drop. The experimental result shows that the bouncing of the ellipsoidal drop can reduce the contact time and maximum bounce height below the spherical one by at least 30% and 60%, respectively. The exceptional rim dynamics at high AR produces a liquid alignment along the principal direction, leading to the symmetry breaking in the mass and momentum distribution and the subsequent fast drop detachment, which is quantitatively rationalized by the numerical study. The distinct features of the ellipsoidal drop impact will provide an insight into shape-dependent dynamics and open up new opportunities for self-cleaning and anti-icing strategies.

Anomalous lattice thermal conductivity in layered MNCl (M = Zr, Hf) materials driven by lanthanide contraction

“…22 The layered transition metal nitrides exhibited diverse good superconducting properties 23,24 and the monolayer p-type ZrNCl recently was predicted to show good electronic transport properties and high figure-of-merit. 25 However, the thermal transport properties of MNCl is barely discussed in contrast to their electric properties. Here, we investigate the lattice thermal transport for MNCl (M=Zr, Hf) based on the first-principles calculations and phonons…”

“Open‐Mouth” Mesoporous Hollow Micro/Nano Coatings Based on POSS/PDMS: Fabrication, Mechanisms, and Anti‐Icing Performance

“…These coatings demonstrate excellent super-hydrophobicity due to decreased spacing between micro/NP spherical features at their surface. At the concentration of 10%, all PDMS-POSS coatings exhibited excellent super-hydrophobicity regardless of the numbers of sprays (1)(2)(3)(4). The water contact angle on these coatings was in the range of 159-164.4° while the sliding angle was in the range of 2.58-1.94°.…”

“…No material was yet found to be truly icephobic , i.e., being able to prevent attachment of ice. Hence, large research effort is directed toward development of effective anti‐icing coatings due to rapidly growing demand for protection of engineering structures against attachment of ice to surfaces of the aerospace, automotive, naval, and architectural structures, in cooling or refrigerating devices, green power generation systems (photovoltaic panels, wind turbines), specialty fabrics and clothing, and many other civilian and military applications.…”

“…No material was yet found to be truly icephobic, i.e., being able to prevent attachment of ice. Hence, large research effort is directed toward development of effective anti-icing coatings [1][2][3][4][5][6][7] due to rapidly growing demand for protection of engineering structures www.advancedsciencenews.com www.particle-journal.com microspheres [18][19][20][21][22][23][24][25][26][27] are difficult, time consuming, and costly, and consequently they cannot be flexibly used as in situ processes in a broad range of industrial domains such as on-site application of anti-icing and other functional coatings onto existing engineering structures.…”

Dynamic behaviours of water droplets impacting on laser ablated surfaces

“…Currently, most of studies only simulated a portion of the water droplet impacting process. As shown in Table 1, For studies at high Weber number, the simulated impacting time varied from 8 to 60 ms [27][28][29]. At the end of the simulation, the water droplet still in a dynamic process and not reached an equilibrium state.…”