  The impact of a heavier droplet into a deep pool of lighter liquid is
investigated using three-dimensional numerical simulations. Unprecedented to
any numerical simulations, we demonstrate that the heavier droplets can hang
from the surface of a lighter liquid using surface tension. The impact
phenomenon and the evolution of the heavier droplet as a function of its size
and release height are explored. A theoretical model is also formulated to
understand the role of different forms of energies associated with the hanging
droplet. We further solve the force balance equations for the hanging droplets
analytically and demonstrate that the results obtained from our simulations
match very well with the analytical solution. This research offers
opportunities in many areas, including drug and gene delivery, encapsulation of
biomolecules, microfluidics, soft robots, and remediation of oil spills.
