Introduction

Regular gravitational potential has a stabilizing effect in that it brings the liquid volume toward the bottom of its container. When the body force diminishes, the liquid volume assumes any location inside its container in an unpredictable manner. The problems of liquid sloshing dynamics under microgravity are different from those encountered under a regular gravitational field. These problems include liquid reorientation and the difficulty of moving and handling, since the body force is almost negligible. Under microgravity, surface tension forces become predominant. The Bond number, given by the ratio of the gravitational to capillary forces, plays a major role in the free-liquid-surface characteristics. For very small values of the Bond number, capillary forces predominate and the free surface will not be flat, but will rise around the vertical walls of a container.

The problems of liquid behavior at a low and zero gravity include the mechanics and thermodynamics of capillary systems, heat transfer in cryogenic tanks and mechanisms of energy transport, capillary hydrostatics, low-gravity sloshing, and fluid handling. The early work on free-liquid-surface behavior under a low gravity field considered different problems of the surface–vapor interface (Petrash and Otto, 1962, 1964, Shuleikin, 1962, Petrash, et al. 1962, 1963, Petrash and Nelson, 1963, Neu and Good, 1963, Paynter, 1964a, b, Zenkevich, 1965, Abramson, 1966a, Seebold et al., 1967 and Hastings and Rutherford, 1968).