Study On Hydrodynamic Performance Of Magnus Ship Anti-roll Device

The navigation state of the ship in the waves is related to the safety of the ship,and the ship anti-roll device has always been valued by people.The existing anti-roll devices have the disadvantages of occupying the space inside the ship or have little effect at zero speed.The Magnus rotary cylindrical anti-roll device can overcome the above two disadvantages and has a good application prospect.In this paper,basic theoretical research on Magnus rotating cylindrical anti-roll device is carried out.At zero speed,the anti-roll device uses forward and backward swing so that the rotating cylinder has a relative flow velocity and thus generates lift.The Magnus rotating cylindrical anti-roll device is simplified as a swinging rotating cylinder,and then the various factors that affect the hydrodynamic performance of swinging rotating cylinder are studied in detail.The main work of this article is as follows:Introduce the basic theory of flow around the cylinder to lay the foundation for analyzing the flow around the rotating cylinder;Introduced the principle of Magnus effect,explained Magnus effect from Bernoulli's principle and boundary layer theory.The basics of computational fluid dynamics are briefly introduced,and grid-independent verification of the grid used in this paper is carried out.The similarity theory of rotating cylindrical test is introduced,and the main parameters affecting the hydrodynamic performance of the rotating cylinder are determined,and performed the rotating cylinder flow test.The results show that the lift coefficient and drag coefficient of the rotating cylinder increase with the increasing rotation speed ratio then decrease.The CFD method was used to simulate the hydrodynamic performance of the rotating cylinder.Firstly,it compares with other scholars' results to further verify the correctness of the numerical model adopted in this paper;Then the effects of the rotation ratio,Reynolds number and roughness on the hydrodynamic performance of a three-dimensional infinitely rotating cylinder are studied.Finally,the effects of the rotational speed ratio,the Reynolds number and the length-diameter ratio on the hydrodynamic performance of a three-dimensional finite-length rotating cylinder are analyzed.The results show that the rotation ratio has the greatest effect on it.The CFD numerical calculation was used to optimize the model and the oscillating control equation of the swinging rotating cylinder.Then,the hydrodynamic performance of the oscillating rotating cylinder model is numerically calculated,and the influence of the oscillating angular velocity and rotation ratio on the hydrodynamic performance of the oscillating rotating cylinder model is analyzed.The basic theory of ship rolling is introduced.The control system and PID control method of the roll reduction device are briefly introduced.The principle of anti-rolling of the anti-rolling device is analyzed in combination with this control method;finally,on the basis of the selected model,simulations were performed on the anti-rolling motions at constant speed and at zero speed.comparing the anti-rolling effect before and after the anti-shake,theresults show that the Magnus rotating cylindrical anti-rolling device ideally has a good anti-rolling effect.