Numerical Simulation of the Effect of Inflow Velocity on the Flow Field Characteristics of Circular Circulating Aquaculture Ponds

To meet the growing demand for animal food among the population, China has proposed the strategy of building a "Blue Granary, " relying on marine space, marine biological resources, and the application of modern marine high-tech. Industrialized recirculating aquaculture (also known as land-based factory aquaculture, factory aquaculture, or industrial fish farming) has the advantages of high production efficiency and small land occupation. It is a high-density, high-yield, high investment, and cost-effective aquaculture method. The recirculating aquaculture system is in line with the "Blue Granary" strategy, effectively reducing water pollution while ensuring food security. Therefore, in recent years, recirculating aquaculture in China has developed rapidly. In this context to achieve intelligent regulation of the inflow velocity of industrial recirculating aquaculture, this article firstly summarizes the three main factors that affect the inflow velocity from previous research: The flow field velocity of the aquaculture pool, the discharge velocity of the bait (residual bait), and the velocity of temperature regulation. With the improvement of computer software and hardware, computational fluid dynamics (CFD) is gradually being applied in various fields. CFD provides cheap tools for simulation, design, and optimization, as well as tools for analyzing three-dimensional complex flows. In complex cases, measurements are often difficult, even impossible, and CFD can easily provide detailed information on all flow fields. Compared with conventional experiments, CFD has the advantages of no restrictions on parameters, lower cost, and no interference in the flow field. This method can be used in aquaculture to solve the problems of temperature control effects, solid particle emission efficiency, and flow zone division that cannot be directly measured in actual production under different flow rates. At present, there are few studies reporting CFD numerical simulation of multiphase flow in aquaculture. Existing research focuses on the impact of the inlet and outlet structure and the shape of aquaculture ponds on the flow field, and the effect of sewage collection. There are few reports on the use of numerical simulation methods to design the regulation scheme of inlet flow velocity. Because of the advantages of CFD, we chose it for simulation. Secondly, the specific model used in the numerical simulation was determined through experimental verification, research di