An experimental study on the internal flow field characteristics in aquaculture vessel tanks under sloshing conditions

An experimental platform was established to investigate the internal flow field of an aquaculture vessel under rolling and heaving motions. The effects of different jet angles (α_jet) and velocities (v_jet), roll angles (θ) and heave amplitude (Z_a), and motion periods (T) were explored. The results show that in the stationary state, the flow field in the aquaculture tank was stable, and the jet conditions affected the flow field characteristics and stability. Under heaving motions, the average velocity (v_avg) exhibited an inverse relationship with Z_a, while the coefficient of variation (COV) demonstrated a non-monotonic trend, with its variation pattern influenced by T. Notably, the heave motion had a negative correlation effect on the v_avg across the entire tank area. With rolling motions, the flow field changes were related to the motion trajectory of the tank. The v_jet had a significant influence on the v_avg which increased as θ and decreased as T increased. Under the combined motion of the two degrees-of-freedom, the v_avg increased with θ. Additionally, an increase in T led to a corresponding enhancement in flow field stability. Under combined heave-roll motion conditions, the v_avg demonstrated a 20–30 % reduction compared to static conditions at identical jet parameters (α_jet, v_jet). These results furnish empirical evidence for refining the hydrodynamic behavior of aquaculture vessels in seaway conditions (e.g., rolling/heaving), thereby enhancing their operational adaptability in fisheries.