Analysis And Study On The Calculation Of Ship Interaction Force And Capability Of Maneuvering Control

With the increasingly close international trade,the demand for trade and transportation is growing,ships are gradually developing to large and high speed,and the navigation density increases.The number of ships entering and leaving ports and cooperative operations has increased,in these cases,hydrodynamic interaction between ships will affect ship maneuvering motion,and the importance of ship maneuvering safety is further enhanced.At present,most studies on ship interaction force focus on the state of fixed course and speed,and less on the motion state of ship affected by the interaction force.Based on the above background,this paper builds a calculation method that can accurately solve the ship interaction force,and considers its real-time influence of the on the ship’s maneuvering motion,adds ship propeller and rudder control to timely adjust the ship’s motion state,and studies the ship’s maneuvering ability under the influence of the interaction force.Based on the above background,this paper firstly establishes a mathematical model of ship motion by using the separated MMG(Maneuvering Modeling Group)model,and takes the KVLCC2 ship as the research object to conduct and valid numerical simulation of the ship maneuvering motion.Aiming at the CFD calculation method of hydrodynamic derivatives and coefficients in MMG model,STAR-CCM+ software was used to simulate oblique towing test.The position hydrodynamic derivatives were obtained by fitting the simulation results and compared with the experimental values.The MMG model is programmed by Fortran language,and the motion differential equation is solved.Plugging in the hydrodynamic derivatives and coefficients obtained by different methods,the turning motion in still water is simulated and compared.Finally,the maneuverability hydrodynamic derivatives and coefficients with high accuracy were selected for the subsequent ship maneuverability control simulation.Then,the first order Taylor expansion boundary element method based on source-couple mixed distribution model is used to calculate the ship interference force,this method can improve the calculation accuracy and efficiency effectively.In view of the ship for arbitrary planar motion,considering the influence of the change of ship normal vector,the interference force is solved under the ship fixed coordinate system(non-inertial system),and compared with the results under inertial system,the correctness of the calculation method under non-inertial system is verified.And effects of the transverse distance and speed on the force and moment are explored.Finally,ship control under ship interference force is considered comprehensively,the part of ship mutual interference force is added into the MMG model.The motion control method is established to control the propeller and rudder of the ship to achieve the control target of speed and heading,and the control of the track is realized indirectly by heading control.KVLCC2 and Aframax are used as simulation objects to simulate the tracking situation of the two ships,and the results show that the control target can be achieved under the present control method.Finally,the influence of lateral tuning parameter and rudder speed on control is explored,and the minimum transverse sailing distance under interference force is discussed.