Research on Cage Layout Mode Based on Numerical Simulation of Flow Field Disturbance Response and Suspended Particulate Matter Diffusion: A Case Study of the Nanpeng Island Wind Power Sea Area in Yangjiang City, China

Clarifying the changes in the flow field, trajectory, and range of particulate matter such as input detritus and feces of marine aquaculture in offshore wind farms is of great importance for optimizing the layout of cage culture, preventing water pollution, and promoting the integrated development of wind power and aquaculture. This study designed multiple scenarios based on the basic data of the Nanpeng Island wind farm. The flow field changes were simulated through a k-epsilon model based on the porous medium model, and the particle diffusion range and trajectory were simulated via the discrete phase model (DPM) and the MIKE 21 model. The results showed that flow velocities in the whole area, except in the region near the wind turbine, were unaffected by the monopile or jacket foundation. The center velocities of the cages decreased by 14.58% and 21.45%, respectively, when culture density increased from 12.5 to 20 kg/m3. In the case of one-way inflow, placing rafts upstream of the aquaculture area can effectively slow down the flow velocity, which is reduced by 45.2% and 32.3% at the inlet and center of the cage, respectively. In the case of the occurrence of unidirectional water flow, downstream raft frames, arranged in a triangular pattern, could align with the cage center axis. Under actual sea conditions, the raft frame could be arranged in an elliptical shape around the cage. The ratio of the length of its major axis to that of its minor axis is approximately 3:1.