Subpatterns of Thin-Sheet Splash on a Smooth Surface

Abstract

When a droplet impacts a smooth solid surface with a sufficiently high inertia, a thin sheet is created and the whole droplet fluid then breaks apart. Thin-sheet creation and threshold pressures in drop splashingLatkaA. Latka, A. Soft Matter201713740747 defined it as thin-sheet splash. In this work, we used a high-speed camera with a long-distance microscope and experimentally showed that thin-sheet splash can be subdivided into three distinct patterns in terms of breakup location. Specifically, pattern 1 is characterized by the breakup of the rim with the thin sheet being intact, pattern 2 by the almost simultaneous breakup of both the rim and the thin sheet, and pattern 3 by the breakup of the thin sheet followed by the breakup of the rim. The effects of the Weber number and the Ohnesorge number on the transitions of these subpatterns were determined over large ranges of their values, and a regime nomogram in the parametric space of We–Oh was obtained.

Experimental Study on Droplet Splash and Receding Breakup on a Smooth Surface at Atmospheric Pressure

“…Similarly, high- Oh liquids (75 and 85% glycerol solutions) only breakup within the retracting process. Remarkably, the liquid films develop outwardly and upwarp in a certain angle with surfaces for all splashing cases, where thin gas films are wedged. ,, In addition, the wedged angle becomes smaller with increasing liquid viscosity …”

“…Hereto, two distinct patterns of droplet splash are observed clearly by identifying that the disintegration of the liquid film occurs at different stages. Previous experimental studies ,,,,, have shown that the film disintegration is a key indicator for the disintegration of an impacting drop. For low-viscosity liquids, the splash is characterized by the separation of at least one secondary droplet from the rim of the spreading liquid film.…”

“…The mechanisms of droplet splash in low -Oh and high- Oh regimes have been illustrated separately from the perspectives of flow instabilities. , We fully recognized that the pure flow instability approach cannot reflect all of the aspects of the phenomena. ,,− However, the criteria adopted by the instability approach are often based on the comparison of characteristic lengths between the liquid film thickness and the wavelength of the neutrally unstable mode. The length-based criteria are essentially compatible with those criteria based on the unbalanced forces, ,, while their fundamental difference consists in the estimation of characteristic lengths or forces.…”

“…Remarkably, the liquid films develop outwardly and upwarp in a certain angle with surfaces for all splashing cases, where thin gas films are wedged. 40,45,46 In addition, the wedged angle becomes smaller with increasing liquid viscosity. 37 Hereto, two distinct patterns of droplet splash are observed clearly by identifying that the disintegration of the liquid film occurs at different stages.…”

Nanoscopic interactions of colloidal particles can suppress millimetre drop splashing

“…21,[54][55][56] Different splashing patterns can be distinguished as the liquid viscosity increases. 57,58 For the more viscous liquids, a separate regime appears between deposition and corona splashing, for which the liquid sheet separates from the surface, but does not break into separate droplets. 51 Interestingly, splashing has not been observed experimentally above a viscosity of about 20 mPa s. It is not clear whether this is due to experimental limitations to reach the splashing threshold, or if it is a fundamental limit for splashing.…”