Modeling and simulation of small free oscillation of liquid in rigid storage tanks of spacecraft

This study investigates the modeling and simulation of small-amplitude free oscillations of liquid within rigid storage tanks used in spacecraft systems. Mathematical models are developed to represent liquid oscillations, including the ideal fluid model, the Stokes boundary layer model, and the linear damping model. Numerical calculations are carried out to determine fundamental dynamic parameters such as natural frequency, mode shape, and damping ratio by applying the finite element method based on the variational principle. These dynamic parameters are then utilized to derive the corresponding mechanical model parameters of the oscillating liquid, including oscillating mass, pendulum length, and the location of the suspension point. The proposed modeling approach is applied to simulate the oscillation behavior in a large satellite fuel tank developed in China, with the computed outcomes validated through comparison with experimental measurements. The results offer a valuable perspective for addressing liquid oscillation phenomena in spacecraft storage tanks and contribute to lowering design costs and enhancing design efficiency in spacecraft development.