Computer simulations to approach surface tension by means of a simple mesoscopic mechanical model

Abstract

A small insect can stand or walk on water surface, drops of mercury do not spread on a solid surface, and a meniscus is formed at the free surface of a liquid contained in a thin vessel. These phenomena can be seen as macroscopic manifestations of molecular interactions and can be explained macroscopically in terms of surface tension. In this study, we deal with an approach to surface tension from a mechanical point of view, presenting a simple mesoscopic mechanical model of surface tension and the results of its implementation in numerical fluid dynamics simulations. Particularly, phenomena like droplet formation without gravity and with gravity when it can drop from a narrow hole like a trickling tap, the formation of a meniscus at the free surface of a liquid contained in a vessel, the behavior of a small piece of solid on a liquid surface, and a sessile droplet are studied. Student and teachers can study the behavior of a liquid due to the surface tension by using the numeric simulations as a “tool” for analyzing several different situations.