Sloshing response in rectangular water tanks under seismic actions considering resonant effects.

This article investigates the sloshing behavior of rectangular liquid tanks under seismic excitations through large-scale shaking table experiments and OpenFOAM-based numerical simulations, focusing on both resonant and non-resonant conditions. It finds that vertical seismic waves have a minor effect on sloshing height and hydrodynamic pressure, especially under resonant conditions where horizontal seismic components dominate. The study reveals that resonant sloshing is characterized by low-order odd sloshing modes and nonlinear behavior, while non-resonant sloshing involves higher-frequency seismic components and natural modes with stronger correlation to seismic input. Existing formulas by Westergaard and Housner accurately predict peak hydrodynamic pressure near the tank bottom under non-resonant conditions but significantly underestimate it during resonance; therefore, a new formula for peak hydrodynamic pressure under resonant seismic excitation is proposed and validated with experimental and real-case data. The research contributes valuable experimental data and insights for improving the design and safety assessment of liquid-storage structures subjected to earthquakes.