The Research Of Fin Stabilizer System Used At Anchor

Anti-roll tank system is the only choice to reduce rolling for ship at anchor or at low speed, but its effect is not very good. The performance of fin stabilizer system is excellent when the ship is at high or medium speed, but it hardly work when the ship is at anchor or at low speed. The ship which needs to be reduced its rolling under different conditions has to equip two kinds of anti-roll systems. The fin stabilizer system is used when the ship is at high speed, and the anti-roll tank system is used when the ship is at low speed or at anchor. The advantage of this method is obvious, but it raises the cost because of the design and maintenance of two different systems, and it also holds more inner space of the ship. According to this actuality, this dissertation discuss a new fin stabilizer system. This fin stabilizer system adopts a new motion control mode, which makes it unlimited to the ship speed, that is to say this fin stabilizer system can work when the ship is at anchor.The generation theory of the lift force on the fin stabilizer system used at anchor comes from the hovering flight of insects, and the motion mode is imitated with insect flapping. According to the special motion mode, the force on the fin in unsteady flow is analyzed, the generation theories of different liquid force is discusses in detail. Further more, the formulas of each liquid forces are deducted. On this base, computational fluid mechanics is used to verify the correctness of the formulas. The theory base of lift force generation is built at anchor.According to the motion regulation of fin, the mathematical models of new fin stabilizer system, whose motion mode is new, are verified. The new model of fin stabilizer system is used in ship anti-roll model. The performance and anti-roll effect of the fin stabilizer system are analyzed and compared with the anti-roll tank system.At last, the special characteristics of the fin stabilizer system are discussed and researched further. And the condition of two pairs of fins installation is discussed generally.Because of the time limitation, this dissertation just establishes a basic framework of this new topic, and provides a train of thoughts for further research.