Experimental investigation of multi-floating structures for suppressing hydroelastic slamming in a shallow-water sloshing tank

Sloshing-induced slamming phenomena pose significant risks to liquefied natural gas (LNG) cargoes in ocean engineering. Although floating particles have been reported to suppress violent free-surface motions, their use in LNG tanks is impractical because collisions between particles and the tank walls may cause secondary impacts and structural damage. To address this challenge, this study proposes a novel conceptual anti-sloshing measure, the multi-floating structure (MFS). A series of experiments was carried out to evaluate the suppression performance and mechanisms of the MFS on hydroelastic slamming. The evolution of the free surface and the MFS motion was recorded using high-speed cameras, and the particle image velocimetry was adopted to obtain the flow velocity. In addition, fiber Bragg grating sensors were used to measure the structural response of the elastic tank wall. The results reveal that the free-surface flow and the MFS exhibit strong coupling. The MFS is passively driven by the free-surface flow. In turn, the MFS motion suppresses steep wave fronts, induces shear flows, and redistributes and dissipates wave energy, thereby suppressing violent liquid slamming. The dominant loading mechanism shifts from impulsive impact loads in the clean tank case to quasi-static loads in the MFS cases, leading to variations of the stress state and deformation pattern of the sidewall. Statistical analysis quantitatively shows that the MFS can effectively reduce the structural response. The MFS with lighter side substructures has superior performance. These findings highlight the promising potential of the MFS in suppressing liquid slamming, providing valuable insights for future practical applications in LNG tanks.