An Experimental Study on the Effects of Deflector Baffles and Circular Fish School Swimming Patterns on Flow Field Characteristics in Aquaculture Vessels

To maximize the limited space of aquaculture vessels and achieve a more efficient layout for aquaculture compartments at the bow and stern, this study proposes two design schemes: modifying the compartment configuration and removing the deflector baffle. The study focused on the impact of compartment configuration and fish movement on the flow field characteristics under the two proposed schemes. The results showed that the mean flow velocity in the octagonal tanks was higher at jet angles of 30° and 45°, with the trend index ($\gamma$) being more stable at 30°. Within jet angles ranging from 0° to 45°, the mean flow velocity increased with rising jet velocity. Retaining the deflector baffle helped stabilize the flow field, making it more effective than scheme A, which, in turn, outperformed scheme B. In circular tanks, the mean flow velocity was higher at 0° and 15°, with the trend index being more stable at 0°. Retaining the deflector baffle at low jet angles further stabilized the flow field. Retaining the deflector baffle at low jet angles helped maintain high average flow velocity, while at high jet angles, it reduced turbulence. Therefore, scheme A demonstrated a better balance between aquaculture volume and flow field stability. Fish simulation experiments revealed that the presence of fish significantly hinders fluid flow and disrupts the stability of the flow field. In practical aquaculture, the jet angle and the use of deflector baffles should be selected based on the tank geometry, while the jet velocity should be adjusted according to the fish species and their swimming speed to establish a flow environment conducive to fish survival and growth.