A Generalized Pressure Load Model on Anti-Slosh Baffles at Different Fill Depths and Slosh Wave Heights

Propellant sloshing can significantly affect both spacecraft stability and the structural integrity of propellant tanks. Anti-slosh baffles are commonly employed to mitigate these effects, with their configuration typically guided by damping requirements. Accurate knowledge of distributed pressure loading is essential for baffle structural design, while the resulting forces and moments are directly relevant to vehicle control system design. Previous experimental studies on rigid ring baffles have characterized liquid pressure loads and associated damping. These studies showed that when the nondimensional velocity parameter exceeds 3.0, the previous theoretical predictions agree with measurements; however, at values below 3.0, existing theories become nonconservative and underpredict pressure loads. In this work, a generalized pressure load model is derived from the principle of energy conservation. Computational fluid dynamics (CFD) simulations indicate that slosh-induced pressure can be decomposed into static and transient components, and that a phase shift in pressure occurs across the baffle, increasing with fluid damping. The maximum load corresponds to a 90° phase shift. Comparisons with comprehensive experimental data validate the proposed theory, showing that when the baffle is submerged, the maximum pressure load model encompasses all measured data. The theory is further extended to predict pressure loads at varying fill depths and wave heights, demonstrating very good agreement with experimental results. The simple mathematical model derived in this study provides a robust predictive tool for pressure loading across different fill depths and slosh wave heights, supporting both structural and control system design.