Study On The Effect Of Wind,wave And Free Surface Coupling On The Stability Of Fishing Boats

In the process of berthing and sailing,the vessel will encounter external torque interference caused by wind and other factors.Under these external moments,the hull will be inclined.If the vessel has appropriate stability,the tilt angle is within the controllable range,the vessel will rely on the role of gravity and buoyancy to generate a restoring torque,in order to resist the external torque,so that the vessel gradually returns to its equilibrium position.This ability to resist external forces and restore the vessel to equilibrium is called vessel stability.Vessel stability is an important guarantee for a vessel to withstand external forces in a complex sea state and to achieve safe navigation.Therefore,the stability of the vessel has a high research value.China has a large number of fishing vessel,accounting for high and wide distribution.Studies show that fishing vessels have a better harvest in bad weather,and fishermen choose to go to sea in bad weather conditions for greater benefit.Because of the complexity of the sea conditions and the changeable operating condition,the stability of fishing vessel is worse than that of large ones,and the current research only considers the effect of single factor on the stability of fishing vessels,and there is no accurate way to analyze and calculate whether fishing vessels are safe in a bad weather,and fishermen can only judge whether they have the conditions of sailing under certain weather.Sometimes miscalculation can lead to tragedy.Therefore,the stability of fishing vessel has a very high research value.At present,most ofscholars are devoted to large ships and military vessels such as container ships,oil tankers,bulk carriers,warships,nuclear submarines,and aircraft carriers.There is little research on fishing vessels.Therefore,a new generation of shipbuilders needs attention.Fishing vessels,concerned about the people's livelihood,closely follow the party's pace,and contributed their own strength to building a well-to-do society.A small number of scholars in the field of fishing vessels study the stability of fishing vessels,most scholars study the stability of fishing vessels under single wind,the stability of fishing vessels under the action of single wave and the stabilization of fishing vessels under the action of single free liquid surface result in no accurate analysis and calculation method to judge whether fishermen have safe and economic benefits to go to sea under a complicated condition,and there is no accurate way to weigh costs and benefits.Therefore,the paper chooses the three-coupling analysis and calculation,which is to analyze and calculate the effect of wind,wave and free surface coupling on the stability of fishing vessels.In order to study the stability of fishing vessel more accurately,make it more safe to go to sea fishing operation,eliminate the hidden danger of operation under bad conditions,this paper mainly works as follows:Firstly,the calculation method of the stability of fishing vessel under the interaction between wind wave and free liquid surface.The wind-blown model perpendicular to the midline of the fishing vessel is selected,in this paper,the stability of fishing vessel under the action of single wind,the stability of fishing vessel under single wave action and the notation of free liquid surface under the action of free liquid surface are calculated respectively by the wave model.Based on the principle of the same linear moment coupled with the same direction addition and the different direction subtraction,the recovery moment of fishing vessel under the action of sudden wind,the recovery moment of fishing vessel under wave action and the recovery moment of a fishing vessel modified by the free liquid surface under the action of the air are superimposed and coupled.Secondly,examples of calculation and analysis.This paper makes use of the fishing vessel built by a shipyard as the calculating material,chooses the load-carrying condition of its not-loaded port as the concrete calculation conditions,analyses and calculates the stability of the fishing vessel according to the above,and draws the conclusion that the difference of the recovery torque under the limit condition of the single variable.Finally,using C language for the preparation of the results of the program.