Large-Amplitude Sloshing Analysis and Equivalent Mechanical Modeling in Spherical Tanks of Spacecraft

Abstract

Liquid sloshing of a large amplitude is prone to take place under excitation, especially when the gravitational intensity becomes small. A composite equivalent mechanical model is established to efficiently and accurately predict the slosh forces and moments exerted on a spherical propellant tank in a spacecraft. The modeling is based on an assumption of the dynamic equilibrium position of the liquid, which changes with time-dependent tank motion. Equivalent gravity is defined to describe the dynamic equilibrium position and act as a restoring force during sloshing. Sloshing of the liquid is assumed to take place around the dynamic equilibrium position. The validity of the modeling method is verified through numerical examples. Good stability and the ability to accurately predict the dynamic response under the violent sloshing of the composite model are revealed.