Hydrodynamic Characteristics And Experimental Study Of Anti-Wave Cages Of Ship Shape

The increasing demand for marine products and the marine pollution caused by offshore aquaculture make mariculture expand to the deep sea.The far-reaching sea area is rich in fishery resources,with strong water exchange,which is conducive to Mariculture,but also has the characteristics of strong current and strong waves.To solve this problem,a single point mooring(SPM)cage system is designed,which can quickly adjust its position when it is subjected to wave current forces in different directions,so that the axis of the floating frame can form a certain angle with the direction of the incoming flow,so as to reduce the effect of the wavelet flow force and minimize the failure risk of the cage in typhoon waves.This ability can greatly reduce the accumulation of aquaculture residues at the bottom of the cage,reduce the deterioration of the local marine environment,and greatly reduce the cost of anchoring and installation.In this study,the structure design of the ship type anti wind and wave cage is carried out.The analysis method,calculation method and experiment method of marine structure design are synthetically used to analyze SPM cage.Combined with the sea data of the cage and the appropriate design parameters,the mooring system,the floating frame system,the net clothing system and the bottom ring counterweight of the cage are designed comprehensively.The theoretical analysis and calculation of the new structure are carried out.Based on the rigid body kinematics and Morison equation,the mathematical model of the floating structure of the cage is built;the wave current force,gravity and buoyancy of the cage are calculated,the damping characteristics of the cage are calculated,and the rigidity of its mooring system is analyzed.Based on the above analysis,the motion equation of the cage is built.Through the hydrodynamic analysis module based on ANSYS Workbench,the numerical simulation of different structural parameters of the cage design is carried out,and the hydrodynamic characteristics of the cage under the joint action of wave and current are analyzed.The influence of various experimental factors on the inspection and evaluation indexes of the cage was analyzed by range analysis.The results show that under the condition of both economic cost and cage safety,the cage with length of 75 m,width of 20 m and head angle of 75 ° has better hydrodynamic performance and relatively low breeding cost.According to the better scheme of numerical simulation,the model test of the new structure cage is carried out.Based on the model similarity criterion,a 1:15 cage model ismade,and the test platform is built and the pool model test is carried out to verify the rationality of the cage design.Finally,according to the design parameters,the SPM cage is manufactured and tested in the field.The sea test results show that the cage works well in the wave environment.