CFD-based optimization of baffles for enhanced damping in liquid sloshing

Liquid sloshing in partially filled tanks is a classical yet challenging problem in fluid dynamics, with strong implications for a wide range of engineering applications, including aerospace propulsion, marine transport, and energy storage systems. The violent oscillations of the free surface may significantly compromise the structural integrity of the container and the stability of the hosting vehicle. Therefore, the mitigation of sloshing through efficient damping strategies represents a key research objective. The present thesis provides a comprehensive numerical investigation of liquid sloshing in cylin- drical tanks, with particular emphasis on the role of baffles as passive devices for the enhancement of energy dissipation. The study combines computational fluid dynamics (CFD) and computational structural dynamics (CSD) simulations within a consistent finite-volume/finite-element framework. The adopted numerical methodology is first validated against benchmark cases from the literature, including mesh sensitivity analyses, temporal convergence studies, and systematic quantification of numerical uncertainties. This validation campaign ensures the reliability of the computational setup and establishes the level of confidence required for the subsequent parametric investigation. Once validated, the framework is applied to assess the influence of different baffle concepts—rigid, flexible, and porous—on sloshing dynamics. The rigid annular baffle configuration, for which high-quality experimental data are available, serves as a reference case, allowing direct comparison between sim- ulations and measurements, and enabling a detailed characterization of the mechanisms of energy dissipation induced by flow obstruction and vorticity generation. Building upon this reference, the analysis is extended to flexible baffles through a fully coupled, two-way fluid–structure interaction (FSI) approach. To the best of the author’s knowledge, this represents one of the first mesh-based FSI investigations of sloshing with flexible baffles available in the literature, providing new insights into how structural compliance modifies the energy exchange between fluid and tank, and how elasticity can be exploited to enhance damping. Finally, the study explores perforated baffles, sys- tematically evaluating how global porosity and perforation pattern affect sloshing attenuation and flow-induced pressure dynamics. Beyond the direct CFD and FSI results, the generated numerical database is used to construct a reduced-order model (ROM) of the sloshing dynamics in the form of a damped pendulum system. The equivalent stiffness and damping coefficients are extracted directly from high-fidelity simulations, yielding a low-dimensional yet physically consistent representation suitable for control-oriented applications. In summary, this thesis develops, validates, and applies a mesh-based numerical methodology for the study of liquid sloshing in baffled tanks. Its novel contribution lies in the integration of a fully coupled FSI framework for flexible baffles, which represents an aspect scarcely explored in previous literature, and in the systematic quantification of damping enhancement mechanisms across rigid, flexible, and porous configurations.