Hydroelastic Responses of a Circular Net Cage Under Wave Action

Abstract The accurate assessment of hydrodynamic loads acting on a fish-cage is a topic that has received considerable attention in engineering. However, the sheer complexity of such a net-type structure makes it difficult to model with computational fluid dynamics (CFD) techniques. This has resulted in empirical methods being most commonly used in engineering practice. The present study proposes an efficient numerical model for predicting the hydro-elastic behavior of net cages under wave action. The finite element method (FEM) based dynamic solver AquaSim was adopted to simulate the hydro-elastic behavior of the net-type structure with a modified Morrison formula being used to estimate the hydrodynamic loads acting on the net structure. Beam elements and truss elements were employed to model the floating collar and mooring lines respectively, and the net chamber itself was modelled by membrane elements. The simulation results show that the net at the top of the cage undergoes more significant deformation due to the surface wave effect. The parametric study revealed that the cage system has an obvious nonlinear relationship with the incident wave amplitude. These findings provide a reference for the engineering design of marine aquaculture systems.