Experimental and Numerical Modelling of an Offshore Aquaculture Cage for Open Ocean Waters

An innovative offshore aquaculture cage design and its hydrodynamic behavior for different environmental conditions is presented. The work involves the following blocks: (i) design of the aquaculture cage, (ii) experimental tests performed at IHCantabria facilities (Cantabria Coastal and Ocean Basin, CCOB), (iii) brief description of the ad-hoc time domain numerical model developed, and (iv) calibration of decay tests and sea states cases, in order to be able to simulate different locations of interest for aquaculture stakeholders. The offshore aquaculture cage is a floating cylindrical structure, designed according to different requirements from standards and needs of contacted aquaculture stakeholders. The cage is focused on the growing and farming of fish species in open ocean conditions. It has been specially designed to be able to withstand different environmental conditions, even waves of more than 5m height. Through numerical and physical modeling, it has been shown that it has a good seakeeping and accessibility, to reduce O&M costs. Motions and loads have been registered during the tank testing to calibrate and validate a specific coupled time domain numerical model developed for multi-body structures to simulate the behavior of the assembled structure (cage and sinker connected by tendons), including non-linear damping forces and a FEM approach to model the mooring and the tendon system.