ABSTRACT
In many terrestrial applications, the force of gravity is by far the largest and, consequently, the smaller effects are neglected. The absence of gravity therefore means that the new fluid dynamics is mainly shaped by the secondary effects. Surface tension, which occurs along the boundaries between two different phases, such as liquid-vapor or liquid-solid, is expected to be a dominant force. The molecules inside the liquid bulk are subjected to attractive forces of neighboring molecules while those near the boundary with the vapor experience an unbalanced cohesive force directed away from the interface. The surface tension force can contribute significantly to the motion of fluids, especially at the interface between liquid bulks and gas bulks. The values of surface tension are obtained by empirical methods or determined experimentally together with the contact angle by measuring the height to which liquid rises in a capillary tube or solid fiber.
