Study On The Influence Of "gate Rudder" On Hydrodynamic Characteristics Of Ship

The gate rudder is a new type of Marine energy saving and maneuvering device,which is similar to the acceleration ducted propulsor.While providing additional thrust,the rudder blades on both sides of the propeller can be controlled separately to enhance the ship’s maneuvering performance.The gate rudder was first fully applied on a container ship in Japan.The results showed that in addition to improving the ship’s propulsive efficiency and saving about 14% of fuel in sea trials,the gate rudder also showed excellent maneuvering,noise and vibration characteristics.Up to now,the research of gate rudder is still in the process of further improvement.On the one hand,the research on the design,energy-saving effect and energysaving mechanism of the rudder is mostly carried out based on the model test,and its design accuracy and time cost need to be further improved.On the other hand,the research on maneuverability of gate rudder is still in the preliminary stage.Therefore,in this paper,based on JBC model ship,CFD method is used to carry out the matching optimization design of gate rudder,explore the energy-saving mechanism of gate rudder and forecast its energysaving effect.The pressure,induced excitation force and flow field characteristics of the gate rudder under various operating conditions were developed considering the stern flow field.Finally,through the research of this paper,a set of fast and perfect design method of gate rudder matching optimization based on CFD is formed.After the gate rudder is installed,the viscous resistance of the JBC ship is reduced,and the energy saving effect is 8.05% at the given speed,and the exciting force generated by the gate rudder is small.In this paper,the numerical calculation of the resistance and self-navigation of the standard model JBC ship is carried out,and the calculated results are compared with the experimental values to verify the accuracy of the numerical calculation method and the meshing strategy.After the parametric modeling of JBC stern rudder was realized based on CAESES,the variable parameter calculation of the stern rudder was realized coupled with CFD platform.The sensitivity analysis of the characteristic parameters of the stern rudder was completed based on the multiple linear regression analysis method.According to the analysis results,the gate rudder model with better matching effect with JBC standard model was obtained.Numerical prediction of the open water performance of the gate rudder and propeller system is conducted,and the impact of the gate rudder on the open water performance of the propeller is analyzed;Then,the integrated resistance and self-propelled calculation of the ship,propeller and gate rudder are carried out,and the influence of the gate rudder on the hydrodynamic performance of the ship hull and the propeller behind the ship is analyzed by comparing the ship,propeller and traditional rudder system.Finally,the hydrodynamic performance of a propeller under wake conditions is analyzed using the axial velocity at the stern propeller disk as an input condition,and compared with a real ship propeller to verify the accuracy of the calculation method;The hydrodynamic performance of the propeller traditional rudder system and the propeller gate rudder system under direct sailing and rotary conditions are calculated and compared;This paper calculates two special operating conditions of the propeller gate rudder system,and explores its operating principles by analyzing the pressure,velocity,and streamline of its flow field.