Dynamic characteristics of liquid motion in partially filled tanks of spinning spacecraft

Abstract

This paper presents a boundary-layer model to predict dynamic characteristics of liquid motion in partially filled tanks of a spinning spacecraft. The solution is obtained by solving three boundary-value problems: an inviscid fluid problem, a boundary-layer problem, and a viscous correction problem. The boundary-layer solution is obtained analytically, and the solutions to inviscid and viscous correction problems are obtained by using finite element methods. The model has been used to predict liquid natural frequencies, mode shapes, damping ratios, and nutation time constants for a spinning spacecraft. The results show that liquid motion in general will contain significant circulatory motion due to Coriolis forces except in the first azimuth and first elevation modes. Therefore, only these two modes can be represented accurately by equivalent pendulum models. The analytical results predict a sharp drop in nutation time constants for certain spacecraft inertia ratios and tank fill fractions. This phenomenon was also present during on-orbit liquid slosh tests and ground air-bearing tests.

Precession-driven flows in non-axisymmetric ellipsoids

“…The case of a precessing fluidfilled container has been studied for over one century because of its multiple applications. These flows are indeed present in fluid-filled spinning tops (Stewartson 1959), gyroscopes, (Gans 1984) or tanks of spacecrafts (Garg et al 1986;Agrawal 1993), possibly affecting the spacecraft stability (Bao & Pascal 1997). Precession driven flows are also present in planetary fluid layers, such as the liquid core of the Earth (Greff-Lefftz & Legros 1999) or the Moon (Meyer & Wisdom 2011), where they possibly participate in the dynamo mechanism generating their magnetic fields (Bullard 1949;Bondi & Lyttleton 1953;Malkus 1968).…”

A rotating fluid cylinder subject to weak precession

“…In the field of aerospace, the stability of spinning spacecraft containing propellant liquids is still a topical question. For instance, the attitude of spinning satellites (see Stewartson 1958;Gans 1984;Garg, Furunoto & Vanyo 1986;Agrawal 1993;Bao & Pascal 1997) is likely to be disrupted by the hydrodynamics of the fluid inside. Consequently, a good understanding of the behaviour of such a fluid-structure coupled system requires a precise knowledge of the dynamics of the rotating contained fluid.…”