Constraint surface model for large amplitude sloshing of the spacecraft with multiple tanks

The large amplitude sloshing problem of a spacecraft with multiple tanks is studied by using a three-dimensional constraint surface model. The mechanical model portrays the liquid as a point mass moving inside the constraint surface, which is the locus of liquid center of mass locations prescribed by slowly rotating the tank in one-g field. Sloshing forces of liquid in propellant tank are calculated with different actuated accelerations and different filling ratios. The simulation results are in good agreement with the computational fluid dynamics simulation results, which confirm the accuracy of the three-dimensional constraint surface model for solving large amplitude sloshing problems. The coupled problem between liquid sloshing and spacecraft body motion is also calculated using the mechanical model, and the comparison between simulation results and the in-orbit experimental results of the Sloshsat FLEVO satellite is discussed.