The rotary sloshing dynamics of liquid hydrogen in tanks can influence load transfer, stability, and safe operation of cryogenic storage systems. This study uses CFD to investigate damping behaviour, force coupling, and energy dissipation in spherical LH2 tanks across excitation frequencies to identify conditions where swirling motion forms and persists. Rotary sloshing appeared at all tested frequencies, although its strength and decay rate varied across the sloshing stability map. Within the planar stability region, rotary oscillations decayed faster than lateral motion, with swirl damping up to 40–50 % higher. Outside this region, lateral motion decayed more rapidly, while swirling persisted as a weakly damped response. A consistent phase shift between orthogonal force components was observed, while kinetic energy analysis showed part of the input energy remained within the swirling mode, sustaining its influence beyond planar oscillations. These results provide clearer insight into how rotary motion governs LH2 sloshing behaviour.
Nuwantha et al. (Wed,) studied this question.