Structural parameter optimization and hydrodynamic analysis of rotatable horizontal aquaculture cage

Abstract

To enhance the stability of the rotatable horizontal aquaculture cage (RHAC) in marine environments, this study proposes an optimization strategy aimed at improving the primary structural configuration, while improving the motion characteristics, ensuring adequate aquaculture space. A parametric model of the RHAC is established, and single-factor experiments are conducted to analyze the effects of different net cage radius (r), net cage cone angle (α), and net cage length (L) on response amplitude operators (RAOs) and displacement, which refers to the movement of the center of gravity of the RHAC relative to the origin. Based on the response surface methodology (RSM), a predictive model for cage displacement and volume is constructed to elucidate the matching relationship between the main structural parameters (r, α, L) and stability. Three sets of optimization schemes are formed by minimizing displacement and maximizing volume as joint optimization objectives combined with single-objective optimization. The predicted values of the optimization design points are compared with corresponding numerical simulation results, with a maximum deviation of 9.04 %, which verifies the effectiveness of the optimization. The research results indicate that the stability and aquaculture space of the cage can be effectively balanced through structural parameters optimization. When r = 10 m, α= 30.001°, and L= 43.415 m, the optimization effect is optimal. Compared to the initial design, cage displacement is reduced by 10.07 %, while the volume increased by 44.70 %. Additionally, the RAOs in the sway, heave, roll, pitch, and yaw directions are significantly reduced. This study deepens the analysis of the hydrodynamic performance of the RHAC, offers theoretical support and design guidance for its engineering applications, further enhances its adaptability and aquaculture efficiency in complex marine environments