RIASSUNTO
ABSTRACT:
In this study a four cage grid mooring system is presented and a set of equations of motion for this flotation structure are derived. The purpose of this study is to investigate the hydrodynamic behaviors of four-cage grid mooring system under wave actions using numerical model. The numerical results are discussed focusing on the deformation of fish nets and the maximum mooring-line forces. The results show that the location of maximum mooring tension is always at the upstream of the mooring system, the wave direction has no effect on the net cage deformation, but it will affect the mooring line tensions.
INTRODUCTION
Recently, the fish stock is decreasing due to overfishing, pollution and climate change. On the other hand, the demand for fish food, however, has grown substantially as the world’s population increases. To deal with this problem, the aquaculture industry is playing an increasing important role in the fish production industry. The fish farm is forcing to move offshore due to environmental impact concerns and multi-use issues. This call for new technological challenges to the design of net cage and mooring system, as the net cage and mooring system are installed at locations more exposed to waves and current. Therefore, it is necessary to know the hydrodynamic behavior of net cage and mooring system in waves. Consequently, much attention is being focused on dynamic response of net cage in the open sea. Net cage mainly consisted of floating collar, mooring lines, sinker and netting. Netting is a basic component of net cage structure. Thus, there is a lot of research devoted to understanding the hydrodynamic behavior of nets in different operating conditions. It is useful in the cage design to understand how the loads on net cage are transferred to the anchor.