Study On Hydrodynamic Force And Characteristics Of Submarine Bow Rudder

The phenomenon of collision between the submarine and the wharf or other vehicles may occur when the bow rudder is too wide.If the the wingspan of the bow rudder is reduced,the lift of the bow redder will decline,leading to the inadequacy of the steering ability.The bow rudder used for operation control belongs to the low aspect ratio wing body,so there is a significant three-dimensional rolling up flow phenomenon in the tip of the wing around the flow field.In result,the hydrodynamic performance of the rudder will decline.Also adding a end plate at the tip of the rudder can effectively reduce the transverse flow and improve the lift of the bow rudder,directly affecting the control ability of the rudder wing.When sailing on the surface of the water or near the surface of the water,the submarine will produce different degrees of swaying motion affected by ocean waves,and the structure of the bow rudder will be affected by the wave force.In serious cases,the bow rudder will be affected by the slamming force.The wave load and slamming load are the key environmental loads for the design of the rudder structure.Basis on this,the hydrodynamic performance of the bow rudder and the flow vortex characteristics around the tip are analyzed by the CFD simulation technique.In consideration of the scale and configuration of the end plate,schemes for 4 types and 6 specifications of the end plate is designed.In addition,the influence of the end plate on the hydrodynamic performance of the rudder wing and the characteristics of the tip flow vorticity is studied,which provides the basis for configuration design of rudder body(the optimum design of the end plate).A numerical simulation model of wave force is established to study the wave force time history characteristics,the wave force frequency response characteristics and wave load distribution of the bow rudder when the submarine is sailing near the surface of water.The motion response of the submarine and the position of its bow rudder in the regular wave is predicted according to the potential flow theory.Through the establishment of the slamming load numerical simulation model,the time history characteristics and the frequency response characteristics of the slamming load of the bow rudder is obtained.In addition,the characteristics of the flow field during the slamming process of the bow rudder are further studied,and the influence of water entry velocity,the shape of free surface and flow velocity on slamming load of rudder wing is further studied.An effective and feasible theoretical prediction method for the wave force and slamming force of the bow rudder is proposed.Through the superposition of the wave spectrum and the wave force frequency response function or the slamming force frequency response function,the wave force(load)energy spectrum or the slamming force(load)energy spectrum is obtained.According to the statistical principle and spectral analysis method,the wave force(load)or slamming force(load)that may be encountered in the actual rudder wing in real marine environment is predicted,to provide the basis for the design of the rudder wing structure.