Research On Modeling And Simulation Of Fin Stabilizer At All Speed

Due to the influence of environmental factors such as waves, wind and ocean currents, all kinds of oscillation will appear inevitably, when ships sailing on the sea. The primary influence of ship six degree of freedom motion is rolling. The safety of ship equipment and comfort of crew are badly impacted by severe rolling.To reduce rolling, variety kinds of anti-roll equipment had been invented, fin stabilizer is the most effective and widely used anti-rolling device. Traditional fin stabilizer only can be used when the ship sailing at medium or high speed, if the ship is sailing at low or zero speed, traditional fin stabilizer cannot work effectively. With the development of naval architecture and marine engineering, people put forward higher request on the stabilization of ship, so it has important practical significance to research anti-roll equipment at all speed.Firstly, Several typical anti-rolling devices are introduced in the thesis, and the operating principle of fin-stabilizer at zero-low speed is analyzed emphatically. Considering the compatibility of zero-low speed with medium-high speed anti-roll fin, longitudinal flap mode is chosen as the working mode of all speed fin. Secondly, the lift models of zero-low speed and medium-high speed fin are built by using hydromechanics. Thirdly, the2D physical model of fin stabilizer is built by using Gambit software, with the help of dynamic-mesh technique of CFD software Fluent, numerical simulation for hydrodynamic characteristics of flapping fin is established and lift characteristic curves under different circumstance are obtained. The simulation results can provide theoretical basis to increase lift.Finally, all speed fin stabilizer control principle is designed and the sea wave disturbance model is established. The PID controllers for zero-low speed fin and medium-high speed fin are designed respectively. The simulation experiment has shown good anti-rolling effect under different speed condition. All speed fin stabilizer has been proved feasible and effective in theory.