The rebound of a liquid droplet from a flat solid surface after a sudden decrease of gravity, as well as its spread on the surface in normal gravity, is simulated numerically using the level set method. The predicted static shape of the spreading droplet in normal gravity is in good agreement with that predicted by the software program, Surface Evolver, while the simulated behaviors of the rebounding droplet show qualitative agreement with published experimental observations in the drop tower.

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... t is found that a series of rebound movements-including deformation, departure, bounce, and oscillation of the liquid droplet-are induced by surface recoil after a sudden decrease of gravity. The rebound ability is enhanced by the gravity decrease and the liquid droplet size. No detachment occurs for droplets with small Bond numbers, where a much weak influence of gravity is exhibited compared with surface tension even in normal gravity. Beyond a certain threshold, the departure time of the liquid droplet increases with its size. The amplitude of the surface oscillation also increases; however, the frequency decreases gradually with the droplet size, which is in agreement with the classical theory of droplet oscillation.