Theoretical Prediction Method And Performance Study Of Asymmetric Catamaran Maneuvering Motion

Asymmetric catamaran consists of a main body and side bodies.It inherits the advantages of large deck area and good roll stability of trimaran and catamaran,and is a new type of ship that has appeared in recent years.Asymmetric catamarans can generate favorable wave disturbances by displacing the front and rear sides of the main side.Due to the smaller side,the wet surface area and friction resistance of the hull are reduced compared with the catamarans of the same size.A well-designed asymmetric catamaran may take advantage of the hydrodynamic performance of catamarans and trimarans,overcome shortcomings,and have unique resistance and wave resistance performance advantages.However,due to the asymmetry of asymmetric catamarans,the left and right maneuvering movements will show different performance characteristics,what are the maneuvering movement characteristics,what kind of performance characteristics,and what advantages and disadvantages,etc.,no research report has been reported.Therefore,it is necessary to carry out in-depth research on the prediction method and performance of the ship’s maneuvering motion theory,to grasp its performance characteristics,and to provide technical support for further understanding of the ship’s characteristics and subsequent researchBased on the characteristics of asymmetric catamaran ship type,this paper studies the numerical simulation method and performance of maneuvering motion in still water.Based on the viscous flow theory method,the lateral force of an asymmetric catamaran during maneuvering motion is relatively non-linear.Theoretical prediction methods and numerical calculation methods are studied.The numerical calculation results are compared with the ship model test results.The feasibility of the theoretical method is verified.Using the given theoretical method,the effects of asymmetric terms on the hydrodynamic derivatives of the oblique towing motion,turning motion,and the higher-order coupled hydrodynamic derivatives are studied.Hydrodynamic changes of asymmetric catamaran’s maneuvering motion under different drift angles and angular velocities were studied by simulating oblique towing and variable drift angle swing arm movement of asymmetric catamaran,and the viscous hydrodynamic derivatives of asymmetric catamarans were obtained.Based on the MMG model,the turning and zig-zag maneuvers and related maneuvering motion parameters of the asymmetric catamaran are predicted and their characteristics are analyzed.The turning and zig-zag maneuvering motion characteristics of forward and reverse steering are studied,and the trajectory and motion parameter changes of turning and zig-zag maneuvering motion steering at different rudder angles are compared and analyzed.Using the given numerical simulation and theoretical forecasting methods,the characteristics of the steering and forward and reverse steering turning and zig-zag maneuvering kinematics were studied for the layout changes between different main hulls of the hull.Based on the above work,the maneuverability of asymmetric catamaran is studied in detail.Studies have shown that the number of viscous hydrodynamic derivatives to be calculated has almost doubled compared to catamarans.The results show that the theoretical methods and mathematical models explored in this study can effectively simulate the slanting motion,variable drift angle swing arm motion of an asymmetric catamaran,and predict the maneuvering motion of asymmetric catamaran.The study found that the left and right sides of the asymmetric catamaran had significant differences in handling performance.It can be seen from the simulation results of different layouts that the change in lateral distance of the side body has a small effect on the maneuvering movement of the asymmetric catamaran.Conducive to improving the slewing performance of asymmetric catamarans,the slewing radius becomes smaller,but the slewing performance is reduced.