Effects of wind on the dynamics of the central jet during drop impact onto a deep-water surface

Xinan Liu, An Wang, Shuang Wang, Dejun Dai

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The cavity and central jet generated by the impact of a single water drop on a deep-water surface in a wind field are experimentally studied. Different experiments are performed by varying the impacting drop diameter and wind speed. The contour profile histories of the cavity (also called crater) and central jet (also called stalk) are measured in detail with a backlit cinematic shadowgraph technique. The results show that shortly after the drop hits the water surface an asymmetrical cavity appears along the wind direction, with a train of capillary waves on the cavity wall. This is followed by the formation of an inclined central jet at the location of the drop impact. It is found that the wind has little effect on the penetration depth of the cavity at the early stage of the cavity expansion, but markedly changes the capillary waves during the retraction of the cavity. The capillary waves in turn shift the position of the central jet formation leeward. The dynamics of the central jet are dominated by two mechanisms: (i) the oblique drop impact produced by the wind and (ii) the wind drag force directly acting on the jet. The maximum height of the central jet, called the stalk height, is drastically affected by the wind, and the nondimensional stalk height H/D decreases with increasing Re-1, where D is the drop diameter, is the impingement angle of drop impact, and Re=ρ aUwD/μa is the Reynolds number with air density ρ a, wind speed Uw, and air viscosity μa.

Original languageEnglish
Article number053602
JournalPhysical Review Fluids
Volume3
Issue number5
DOIs
StatePublished - May 2018

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