Modeling And Simulation Of Ship Manoeuvring Motion In Various Speeds And Rudder Angles

In recent years, the study on ship maneuvering mathematical model was taken on two aspects, the first is according to the basic equations of ship motion, solving the motion parameters, then establish it's model; the second is according to the theory of control, seeing ship as a dynamic system. This paper studies on the ship maneuvering performance under various speeds and rudder angles. With "YuLong" for example, its Nomoto model and improved Nomoto model were established respectively, then through turning test to validation its accuracy. For usage of the MMG there is many mistakes in domestic, through the study on it's principles, the MMG model of "YuLong" was established in this paper. Through the study on different methods of establishing models and analysis on some problems to proposed some advices on how to improve the models.Through the study on the process of establishing Nomoto model, I found that it has no consideration on the interference of different rudder angles. This paper modified some linear hydrodynamic derivatives according to the study of Clarke, then through Simulink to simulation the model. The results indicate that the factors of the simulation were conformed with the trial voyage condition, so the models are valid.In the process of establishing the model of hull and propeller followed the theory of MMG, but then using flow field simulation calculation method to establish the rudder model. First the physics model of hull,propeller and rudder were established with Solidworks, then importing them into Fluent to calculate the force on the rudder which was in the complex flow at ship tail, avoiding some simplify process, to ensure the precision of the results.In the process of simulation I found some questions, for the turning angular velocity many references using discrete points to characterization different values of K and T, but this methods will have influence on the accuracy of the test results. Through calculating the values of K and T with different speeds, then it can regression these results into a continuous functions. So through this method it can use these continuous functions to improve the simulation' precision.