| Because of the progressive development in twin-propellers &twin-rudders vessel, research towards the hydrodynamic performances of the ship is becoming increasing important. But up to now, it is mainly through experiments. The theoretical development has only begun. The thesis is based upon the panel element method to predict the hydrodynamic performances of the ship, and through numerical method to analyze and emulate the twin-propeller system by a CFD software FLUENT. The thesis mainly includes such aspects as follows:The panel element method is taken to calculate the hydrodynamic performance of a 3D rudder in steady condition. And according to the 3D airfoil model considering the influence of the tip vortices, The hydrodynamic performance of various L/b is calculated in open water numerically. The results are compared with the experiment and the calculation taking no account of the influence of the tip vortices.The hydrodynamic performance of the screw propeller is calculated by the panel element method in steady condition, and analyzed the induced velocity field of the backwash of the propeller.The mutual interference of a single propeller &twin-rudder is calculated by an iterative program and compared it with the test result of a Germany river boat institution, which fitted it very well. And then the model is founded of the twin-propeller &twin-rudder system, and predicted the performance in steady condition by the method above.A CFD software FLUENT is adopted to emulate and analyze the system, which presented the surface pressure distribution and velocity distribution of the propeller and the rudder. when, What would happen to the resistance of the ship is also calculated considering one propeller broken down, and drew out the backwash of propeller that remained, which would be helpful to some research concerned. |
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