Research On Hydrodynamic Characteristics Of Deep-sea Carrier Unpowered Floating

With the deepening of the development and utilization of the ocean and the increasing importance of the maintenance of marine space rights,underwater vehicles play an increasingly important role.As a special underwater vehicle,the unpowered carrier has the characteristics of isolating the internal payload from the marine environment,and uses the unpowered floating method to transport the deep-sea payload from the sea floor to the water surface.At the same time,it can also meet the requirements of some payloads on the carrier's water-exit speed and attitude,so it is widely used in the fields of seabed resource exploration and exploitation,underwater submarine launched missile,submarine launched UAV,etc.The hydrodynamic characteristics of the unpowered floating process and water-exit process is the core of deep-sea carrier unpowered floating and launching technology research.The research contents include the trajectory,hydrodynamic characteristics,hydrodynamic phenomena and mechanism of the carrier's underwater unpowered floating.The purpose of the research is to obtain the external force distribution of the carrier during the floating process and the water-exit attitude parameters,and provide input conditions for the force analysis,load calculation,strength check,and attitude design of the carrier.In this paper,the hydrodynamic characteristics of deep-sea carrier unpowered floating are studied from the aspects of shape optimization of carrier,numerical calculation method of carrier unpowered floating,test verification of carrier unpowered floating,dynamic simulation of carrier unpowered floating and the influence of external environment disturbance on the water-exit attitude of the carrier.The main research contents are as follows:(1)Through the Box-Behnken test design,response surface approximate model and the optimization method of various optimization algorithms,the shape optimization of the carrier is completed with the minimum resistance coefficient as the objective.(2)The force in the unpowered floating process of the carrier is analyzed,and the motion model of the steady state of the carrier is established.The main factors affecting the floating parameters and the key hydrodynamic dimensionless factors are determined.The numerical simulation test of the towed pool was carried out by using the CFD method.Each key hydrodynamic dimensionless coefficient was obtained by polynomial fitting.The equation of equilibrium state of the carrier unpowered floating at high angle of attackis is established.(3)For the dynamic simulation of the unpowered floating process of the carrier,a set of numerical calculation methods based on STAR-CCM+overlapping grid technology,DFBI and VOF wave model is proposed.The accuracy of the numerical calculation method is verified by the test data of REMUS 100 model and the scale model pool test.(4)The CFD method is used to simulate the unpowered floating process of the carrier.The effects of the position of the floating center,the net buoyancy,the rudder angle and the initial release speed on the inclined climbing floating parameters of the carrier are studied.The influence of the position of the floating center,the rudder angle and the current on the space rotation floating parameters of the carrier are studied.(5)Based on the analysis of the trajectory of the fluid particle of plane wave,the "circle criterion" of the wave force on the carrier at the water-exit moment is put forward,and the effects of wave on the attitude of the carrier are studied from four aspects:phase,direction,wavelength and level of sea state.The influence of the magnitude and direction of the current on the floating parameters is also studied.