Numerical Simulation Of The Flow Field And Particle Settling Inside And Around The Square Net Fishing Cage

China has a long history of fishing and is the largest aquaculture country in the world. With the dramatically growth of economy in China, the demand of Chinese people for aquatic food is increasing fast. To meet this need, cage farming become popular across China’s coast province and zone since the late1970s. To make the most economic profit, a lot fishing cage are distributed in China’s inshore waters and fjords which are slow in water flow and free from billow and swift sea-current. However, these waters also have problems, such as, low water exchange rate and vulnerable to the pollution from cage farming as well as from inland.Due to so many these kind of cages installed in the inner bay to free from pillow and swift sea-current, environment problems have been caused. It is necessary to do some research on the flow field and aquaculture wastes dispersion inside and around this kind of net cages to reset the distribution and scale of cage farms.In this paper, a three-dimensional (3D) CFD model is established to simulate the flow field of the net cages in a uniform current. The realizable k-e turbulence model was chosen because of the viscous flow downstream of the net cages, and the porous media was used to model the fishing net panel. To calculate the flow field and the particle substance transportation, DPM model was set for the simulation. The CFD software Fluent was used to run the model by a way of finite volume to solve the governing equations.The simulation method was validated by comparing the results from the simulation and the physical model test. In the last section of this paper, the simulation results are discussed in terms of the velocity reduction in different directions.