Dynamics of cages for offshore aquaculture
The increase in global demand for food products due to the expanding population in the world has been one of the main concern of nations during the last decade. A solution in terms of sea products has been aquaculture which is basically the production of fish under control conditions in land or protected areas near the coast line. This industry has had great influence in the economies of countries such as Norway and Chile; however due to environmental concerns and space limitations, its growing has been jeopardize and the industry is looking for new frontiers for expansion and efficiency. The natural path for the aquaculture industry is go to more exposed locations in the ocean. In these areas space is unlimited and natural conditions are optimal for culture of different species with minimum impact for the environment. This rises the necessity for research in the interaction between cages, feeder platforms and mooring system under combined current, wind and wave loads. So far research has been done considering arrays of cages either in the surface or in underwater position using traditional spread mooring lines. Generally numerical and experimental studies have been focused on a single cage exposed to a combination of regular waves and currents. This is the main motivation of this research, to develop a numerical model able to handle a complex sea state including irregular waves and a current profile as expected in high energy sea locations. At the same time, the coupled dynamic response of a system including a platform, able to supply food to the fish in the cage during days with no human intervention, is still a niche for further investigation. In our research we integrate the diffraction radiation theory used in offshore industry to calculate the response of offshore platforms integrated with cages for the aquaculture industry. This research seeks for the full description of the dynamic response of complex systems able to grow multiple species in exposed offshore sites. The final goal is to contribute to the expansion of the offshore aquaculture industry using the knowledge gathered during years in the oil and gas offshore engineering field.