Engineering analysis of a submersible abalone aquaculture cage system for deployment in exposed marine environments

• We developed a commercial-size submersible abalone cage grow-out system.
• Computational fluid dynamics for flow field characteristics and numerical modeling of hydrodynamics were performed.
• The abalone plate shelters should be placed parallel to the flow.
• Submerging the system would be critical in any high-energy storm event.

Great potential may exist in the development of abalone aquaculture in underutilized, exposed marine environments. Abalone is a shellfish that feeds on kelp and as a product, can often render high market value. In this study, the development of a commercial-size, submersible abalone cage grow-out system with a modular box structure is described. The flow field characteristics within the abalone containment structure were analyzed with computational fluid dynamic software. The hydrodynamic response of the moored containment structure was investigated with a Morison equation type finite element model that simulates fluid-structure interaction. Environmental forcing input to the model consisted of loading conditions representing combinations of currents with a magnitude of 1.0 m/s and irregular seas with a significant wave height of 8.01 m and peak period of 12.52 s. Simulations were performed with the abalone cage model in both surface and submerged configurations. From the simulations, the attachment loads were determined and used in a structural model to calculate local stresses. Structural analysis of the deployment and recovery operation was also investigated. The results indicate the importance of including a combination of detailed structural/hydrodynamic/flow analyses into the design framework to avoid catastrophic failures of abalone farming systems.