Structural Analysis of Aquaculture Nets: Comparison and Validation of Different Numerical Modeling Approaches

The performance of three different numerical methods were compared and evaluated against data from physical model tests of nets subjected to a static load due to water currents. A parameter study of a simplified net cage model subjected to a steady flow was performed by all methods, varying the net solidity and the flow velocity. The three numerical methods applied models based on springs, trusses, or triangular finite elements. Hydrodynamic load calculations were based on the drag term in Morison's equation and the cross-flow principle. Different approaches to account for wake effects were applied. In general, the presented numerical methods should be able to calculate loads and deformations within acceptable tolerance limits for low to intermediate current flow velocities and net solidities, while numerical analyses of high solidity nets subjected to high current velocities tend to overpredict the drag loads acting on the structure. To accurately estimate hydrodynamic loads and structural response of net structures with high projected solidity, new knowledge and methods are needed.