Fluid–Structure Interaction Modeling of Sloshing Dynamics with Flexible Baffles

This study presents a comprehensive analysis of sloshing dynamics in rectangular tanks equipped with flexible antisloshing devices (ASDs), focusing on how varying baffle elasticity influences fluid–structure interaction (FSI). Three configurations, differing in baffle submergence, are investigated using a two-way partitioned numerical approach. This framework integrates the finite element method for structural modeling with the finite volume method and a volume of fluid approach for free-surface reconstruction. Numerical decay tests are conducted to evaluate the system’s damping characteristics and sloshing frequencies. Furthermore, a reduced-order acoustic-structural model is introduced to efficiently predict fundamental frequency shifts across different flexibilities and submergence levels. This reduced-order model demonstrates strong agreement with the full-order FSI simulations, yielding a maximum relative error of approximately 4% when its foundational hypotheses hold, thereby confirming its value as a computationally inexpensive design tool. Crucially, the study reveals that the elastic restoring motion of the flexible baffle enhances coherent vortex formation. This phenomenon strongly aligns with the evolution of the fluid’s energy dissipation rate, indicating that increased vorticity is critical for effective damping. Ultimately, these findings demonstrate that flexible ASDs can match or exceed the damping performance of rigid counterparts while significantly reducing structural weight.