Numerical modelling of sloshing in a horizontal circular tank under horizontal excitation using smoothed particle hydrodynamics

The most recent Blind Test community exercise conducted by the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) investigated isothermal sloshing in a partially filled horizontal circular tank. In this study, sloshing dynamics under horizontal excitation are modelled using the three-dimensional smoothed particle hydrodynamics (SPH) method, implemented in the GPU-accelerated DualSPHysics code, together with the improved modified dynamic boundary conditions (mDBC) for enforcing the no-slip boundary condition. Considering that previous SPH studies have mainly examined sloshing in rectangular tanks under horizontal and rotational excitation, this study systematically assesses SPH performance for horizontal circular tank sloshing across different fill levels, excitation conditions, and response regimes. The model is evaluated against experimental free-surface elevations through time-series, steady-state, and frequency-domain comparisons, yielding NRMSE values of 3.79–6.42% and dominant-frequency errors below 0.04% for the non-resonant cases. For the resonant case, the NRMSE is reduced from approximately 20% in the previous blind-test setup to approximately 6%. These results demonstrate the importance of accurate boundary and dissipation treatments for capturing sloshing dynamics in a curved and confined geometry. This study demonstrates the capability of the present SPH model as a robust and versatile tool for modelling complex sloshing dynamics in partially filled horizontal circular tanks.