This paper focused on the force characteristics of mooring lines of the common used gravity cage and sea station cage under floating status. In this experiment, total four cage models were designed which included two ...This paper focused on the force characteristics of mooring lines of the common used gravity cage and sea station cage under floating status. In this experiment, total four cage models were designed which included two gravity cage models, one sea station cage model and one quasi-sea station cage model. The gravity cages were made of the same materials but with different weighting system configurations. The sea station cage model and the quasi-sea station cage model were of the same diameter but the latter is 1.4 times in cage height to the former one which attributed greatly to the amplification of effective aquaculture volume up to 2.2 times. Four mooring lines were attached to each cage model on one side and the other side fixed on the bottom of the wave-current tank. Several kinds of experiment conditions were set, including pure current conditions, pure wave conditions and combined wave-current conditions. Forces were measured by four transducers attached to the bottom of the mooring lines respectively. Analysis was based on the resultant forces of the two current-ward or wave-ward mooring lines. Results from this study were presented and statically analyzed revealing that the quasi-sea station cage model suffered from greater forces compared with the other two kinds of cage models, which was more apparent under pure current conditions. It was interesting to find that the mass of the weighting system turned out to be relatively small effect on the forces acting on the gravity cage models under most conditions. Under pure wave conditions, several results of the forces acting on the gravity cage with heavier weighting system configuration were even smaller than those with lighter weighting system configuration. Conclusions were drawn that it was feasible to increase the mass of the weighting system properly to reduce the deformation of the netting system since it will not increase the forces acting on the gravity cages apparently. But it should be kept in mind that the operation of the cage will be affected directly by increasing the mass of the weighting system. As to sea station cage model, given the similar maximum aquaculture volume, results showed that the forces acting on it were approximately the same with that of gravity cages under the same conditions. But its huge size would lead to bad operation directly. Thus, when considering the force characteristics, the performance and management of the cages together with the cage prices, the co-authors recommended that gravity cages were more suitable currently as deep-water aquaculture facilities in China.展开更多
文摘This paper focused on the force characteristics of mooring lines of the common used gravity cage and sea station cage under floating status. In this experiment, total four cage models were designed which included two gravity cage models, one sea station cage model and one quasi-sea station cage model. The gravity cages were made of the same materials but with different weighting system configurations. The sea station cage model and the quasi-sea station cage model were of the same diameter but the latter is 1.4 times in cage height to the former one which attributed greatly to the amplification of effective aquaculture volume up to 2.2 times. Four mooring lines were attached to each cage model on one side and the other side fixed on the bottom of the wave-current tank. Several kinds of experiment conditions were set, including pure current conditions, pure wave conditions and combined wave-current conditions. Forces were measured by four transducers attached to the bottom of the mooring lines respectively. Analysis was based on the resultant forces of the two current-ward or wave-ward mooring lines. Results from this study were presented and statically analyzed revealing that the quasi-sea station cage model suffered from greater forces compared with the other two kinds of cage models, which was more apparent under pure current conditions. It was interesting to find that the mass of the weighting system turned out to be relatively small effect on the forces acting on the gravity cage models under most conditions. Under pure wave conditions, several results of the forces acting on the gravity cage with heavier weighting system configuration were even smaller than those with lighter weighting system configuration. Conclusions were drawn that it was feasible to increase the mass of the weighting system properly to reduce the deformation of the netting system since it will not increase the forces acting on the gravity cages apparently. But it should be kept in mind that the operation of the cage will be affected directly by increasing the mass of the weighting system. As to sea station cage model, given the similar maximum aquaculture volume, results showed that the forces acting on it were approximately the same with that of gravity cages under the same conditions. But its huge size would lead to bad operation directly. Thus, when considering the force characteristics, the performance and management of the cages together with the cage prices, the co-authors recommended that gravity cages were more suitable currently as deep-water aquaculture facilities in China.
