A Study On Anti-wind And Wave Of Single-point Mooring Ship-type Cage

In recent years,coastal aquaculture has been saturated,and far-reaching sea area is vast,rich in fishery resources,stronger water exchange,the development of marine aquaculture from near shore to far-reaching sea has become an inevitable choice.Offshore cage is an efficient and far-reaching marine breeding facility that needs to work steadily under strong currents and high winds.The traditional multi-point mooring round cages used today are vulnerable to damage in harsh sea conditions.Therefore,it is necessary to design and study cages that are more resistant to wind and waves.This paper designs and studies a new type of single-point mooring(SPM)anti-wind and wave of ship-type cage.The unique triangular structure of the head of the ship-type cage reduces the area of the front facing waves.The positioning method of the cage is a single-point mooring,this structure allows the ship-type cage to swing around the anchoring point.When affected by different wave currents,it is possible to adjust the position of the cage itself,reduce the wave flow force,reduce the risk of failure,to achieve wind and wave resistance.At the same time,the cultured residue is dispersed in a larger area to reduce pollution.The main work is as follows:According to the dynamic basis of the cage such as wave theory and the calculation of the floating body,the structure design of the single-point mooring anti wind and wave shiptype cage is carried out.Based on the Froude similarity principle,the cage physics model was made,and through the pool experiment,the cage motion response and mooring system time domain analysis are discussed under different wave flow conditions and different mooring structures.The numerical model of the cage,which is fully consistent with the parameters in the pool experiment,is established,and the hydrodynamic characteristics of the ship-type cage floating frame system and mooring system are simulated and analyzed by using the finite element(FEM)numerical simulation method and with the help of ANSYS Workbench.Compared with the experimental results,the numerical model was analyzed through the gap between the results,and the numerical model parameters were modified to verify the validity of the numerical model.In the numerical simulation,according to the actual size of the single point mooring ship-type cage,based on the static hydraulic analysis,the motion attitude and force of the cage under the sea conditions of the combination of regular wave and wind and flow are analyzed.Establish a graph of wind speed,cage structure,anchor rope length and floating frame motion response and anchor rope force.Among them,the single-point anchoring structure will be subject to greater overlay load under wave-flow coupling,the motion response is more complex,and the feasibility of single-point anchoring is verified by analyzing the difference in time domain response between single-point anchoring and multipoint anchoring cable.On the basis of the numerical simulation of regular wave flow,the cage is a high damping system,the wave frequency response and the low frequency response have different contribution rate to the motion response of the floating frame.And finally proved that the cage can run under the harsh sea conditions once in twenty-five years.At last,during the five-month sea trial,the cage still operated stably three months after the "Candu" typhoon,it shows that the cage can resist 9～11 level wind and waves under actual sea conditions.