Hydrodynamics of recirculating aquaculture tanks with different spatial utilization

In order to maximize the spatial utilization of Recirculating Aquaculture System (RAS) and improve conditions for the growth of farm-raised species, the hydraulic performances of a single-channel RAS with different spatial utilization were researched. A numerical simulation model was established by reference to the experimental model, and the validity of the method was verified by comparing it with the experimental results. Firstly, three-dimensional unsteady models were established by replacing a rectangular tank with a circular arc tank. Then, the hydrodynamics of recirculating aquaculture tanks were analyzed, including velocity distribution, vorticity strength, energy effective utilization coefficient, and the flow uniformity index. Furthermore, flow characteristics, including the evolution of turbulent structures and the relevant influence factors, were also analyzed. Finally, a comprehensive performance index was proposed, which can effectively evaluate the spatial utilization and hydrodynamic characteristics for different aquaculture tanks. The results indicate that with the increase in fillet radius of the tanks, the turbulence intensity in the flow field gradually weakens. The generations of low-speed mixing zone of the culture tank are significantly improved, and the flow uniformity index shows an overall upward trend. In addition, there is a positive correlation between the effective energy utilization coefficient and the flow uniformity index. When spatial utilization of the tank is in the range of 95.3–98.4%, the comprehensive performance index is relatively large. Such an inclusive analysis explores the hydrodynamics in the aquaculture tanks with different structures and recommends the maximization of space utilization. • To maximize the spatial utilization of Recirculating Aquaculture System (RAS) and improve environment for the growth of farm-raised species, the hydraulic performances of a single-channel RAS with different spatial utilization were researched. • An effective numerical method was proposed to study the hydrodynamics of industrial recirculating aquaculture tanks. • A comprehensive performance index was proposed to evaluate the spatial utilization and hydrodynamic characteristics of aquaculture tanks.