Numerical Calculation Of Aerodynamic Performance,Motion Modeling And Simulation For Sailboat

In recent years,sailboat has unique value in the shipping industry due to its energy-saving and pollution-free emissions,especially in marine data collection and environmental monitoring.At the same time,the vigorous development of sailing has also received widespread attention.For sailboat,it is difficult to maneuver because of its dependence on wind energy as a power feature.Therefore,research on sailing performance and handling issues has important theoretical and practical value.Based on the computational fluid dynamics theory,the numerical analysis of the aerodynamic characteristics of the sailboat is carried out.Combined with the mathematical model of the maneuvering motion of the sailboat,the controllable area of the sailboat is calculated and the joint strategy of the sail and rudder is proposed.In addition,the virtual simulation system is designed to simulate the three-dimensional virtual motion of the sailboat.Firstly,to solve the mutual influence problem of the aerodynamic performance between the sailboat hull and the sail,the aerodynamic characteristic of whole sailboat is numerically simulated.By contrast,it is verified that there is a strong nonlinear interference between the aerodynamics of the sail and the hull.Under the different relative wind directions,the maximum thrust coefficients of the whole sailboat is obtained according to the variation curve of the sailboat aerodynamic forces with the angles of attack.The best rules of sailing under different relative wind directions is generated.The overall aerodynamic database of the sailboat is established,which is fitted into a functional relationship based on the variation curve of the sailboat aerodynamic force with the angle of attack of the sail.Secondly,the sailboat is divided into four parts:the rudder,the hull below the waterline,the keel and the sail,and the hull above the waterline.The force analysis and modeling of each part are carried out,and the functions obtained from the calculation of the aerodynamic force of the sailboat are substituted.A mathematical model of four-degree-of-freedom sailboat maneuvering motion considering sea wave disturbance was established.The motion simulation is based on the mathematical model,and the influence of sail and rudder manipulation on the sailing state is analyzed.Next,in view of the safe sailing of sailboat under different wind forces,considering the balance between the aerodynamic force and torque on the waterline and the dynamic and torque under the water line,the wind speed boundary and controllable area of the sailboat in wing at the different sail angles under the different rudder angles and is calculated.A reasonable proposal for handling sail and rudder is proposed to enhance resistance to wind of the sailboat based on the analysis of the calculation results.A simulation of the direct sailing movement of a sailboat controlled by a PID autopilot system aims at the minimum adjustment time and the maximum sailing speed.By comparing the simulation results under different attack angles,the optimal integrated control strategy of sail and rudder in the whole real wind directions is generated.Finally,in order to better represent the realism and real-time performance of sailing,a virtual simulation system for sailboat was designed.The 3ds Max 3D software is used to build a model with high similarity to the actual sailboat.The virtual reality ocean scene is built by the Unity 3D engine,and the model is imported to realize the virtual motion of the sailboat.And through the test of each part of the virtual system,the simulation system designed on the surface of the test results meets the design requirements.