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

Droplet impact on a smooth solid
surface at atmospheric pressure
was experimentally studied and physically interpreted. A particular
emphasis of the study is on the effects of liquid viscosity on the
transition between droplet deposition (or droplet spreading without
breakup) and droplet disintegration (including droplet splash and
receding breakup). Specifically, the critical Weber number separating
droplet deposition from droplet disintegration decreases and then
increases with increasing Ohnesorge number (Oh).
The splash in the low-Oh region and the receding
breakup in the high-Oh region were analyzed qualitatively
based on the unbalanced forces acting on the rim of the spreading
or receding liquid film. A semiempirical correlation of droplet deposition/disintegration
thresholds is proposed and well fits the experimental results from
previous and present studies over a wide range of liquid viscosity.