Surface Ship Motion Simulation And Maneuvering Prediction With Six Degrees Of Freedom Based On CFD

With the promulgation of IMO maneuverability standards,the maneuverability of ships is becoming more and more important in the preliminary design stage of ships.Modern ships are gradually developing in the direction of high performance and professionalism,and the sea conditions they face are becoming more and more complicated.The influence of swaying motion in the maneuvering motion cannot be ignored.It is very necessary to predict the ship maneuvering motion with six degrees of freedom.Based on the CFD software Star-CCM+,the constrained ship model simulation method and the self-propelled ship model simulation method are established for the six-degree-of-freedom maneuvering motion prediction problem of surface ships,and the six-degree-of-freedom maneuvering motion is verified and predicted.The research content mainly includes the following several aspects:First,based on the idea of separate modeling,analyze and simplify the fluid inertial force,viscous force,propeller force,rudder force and external wave force in the equation,and establish the ship’s six-degree-of-freedom maneuvering motion equation.In order to solve the hydrodynamic derivative related to the ship’s horizontal plane,numerical simulation of the ship’s straight-way movement,oblique movement and plane movement mechanism is carried out,and the force and moment of the ship are analyzed based on the calculation results with the speed,drift angle and amplitude.Regress to obtain the corresponding hydrodynamic derivative,compare it with the test data to verify its accuracy,and finally analyze the free surface waveform and hull wake field under different working conditions to explore the hull hydrodynamic force and flow field flow in the constrained motion of the water plane Mechanism of action between.In order to completely obtain the hydrodynamic derivative of six degrees of freedom,the pure heave and pure pitch motion used in the vertical surface modeling of the underwater vehicle are introduced into the solution of the hydrodynamic derivative of the surface ship,and the roll attenuation,pure heel,pure heave and pure pitch motion of 5415 are numerically simulated.Obtain the hydrodynamic performance of the ship in swaying motion,analyze the changes in the force and moment of the ship with heel angle,speed and frequency,solve the relevant hydrodynamic derivative,and finally constrain the flow field information around the hull in different vertical planes in motion Analyze and discuss the mechanism of the hydrodynamics of the hull in the constrained motion of the vertical plane.The CFD-based constrained ship model simulation method and the self-propelled ship model simulation method predict the ship’s six-degree-of-freedom maneuvering motion in still water and regular waves.The prediction results of the two methods in still water are compared with the experimental data to verify the calculation method In addition,the prediction results of the two methods in regular waves are compared,and the results are basically consistent,indicating that the CFD-based six-degree-of-freedom constrained ship model simulation method established in this paper is feasible.Finally,the CFD-based constrained ship model simulation method is used to predict ship maneuvering motion in still water and regular waves under different working conditions,and the influence of rudder angle,wave amplitude,wavelength and wave direction on ship maneuvering motion is analyzed.