Research On Vehicle Trajectory Simulation Of Underwater Vertical Movement Supercavitation Vehicle

The supercavitating weapon of underwater vertical movement can formsupercavity in deep water to reduce resistance. It can sail upward at high speed toattack some targets such as submarines, warships and so on, with the advantage ofhigh speed and high success rate.The research object of this thesis is the supercavitating vehicle of underwatervertical movement. Due to the prensence of cavitation, it is different from ordinaryvehicle in terms of force analysis. Because of the influence of the gravity field,cavity external pressure changes with depth. So there is some difference betweenvertical movement and horizontal movement in the aspect of cavity shape. Thereforethis thesis use simulation to analysis missile trajectory characteristics of the verticalmovement supercavitating vehicle. The main work is as follows:According to the basic principle of cavitation and independence principle of thecavity section expansion, we have study the cavity shape of the vehicle’s underwatermovement and compiled program to calculate the cavity shape. The influence ofcavitation number, Froude number and fluid pressure gradient have been study oncavity shape.The kinematic and dynamic model have been established on the supercavitatingvehicle of under vertical movement. Firstly, the coordinate system has been defined.Then the calculation method of force for cavitator has been given. According to thesituation of wet area, the vehicle has been divided to analyze fluid dynamics andadded mass. Finally, underwater movement equations have been founded which wassolvable by numerical methods.Missile trajectory simulation program has been compiled. This thesis’ssimulation model has been designed by the underwater projectile test model inGerman. On natural cavitation and ventilated cavitation, the supercavitating vehicleof vertical movement has been simulated. Missile trajectory characteristics havebeen analyzed. The influence of parameters to the law of vehicle motion have beenstudy by the comparison of different working conditions. Due to the relationbetween cavity and ventilation rate, speed, depth, ventilated law has been putforward to study the vertical movement of supercavitating vehicle.