Study Of Load On Cavitation Exceeding Water Process Of Vehicle With High Speed

In the shipbuilding and ocean engineering field submarine vehicle with high speed is paid more and more attention by the world’s military powers in recent decades. It is one of the key technologies to predict the change of load and trajectory under the water. When the submarine vehicle runs in a high speed, cavitation is generated partially around the body. With the influence of cavitation, going out of water is a very complex physical process associated with interaction and transformation of three phase including water, vapor and air. Besides, high frequency load is acted on the structure in the process. Therefore, the paper studies the load of high speed submarine vehicle with cavitation based on the method of CFD. It gets underwater trajectory and the change law of vehicle by the numerical simulation. The result is significant to design and improve the structure of shipbuilding and ocean engineering.Firstly, the paper builds numerical model. It simulates the process by Mixer multiple model,modified RNG k-ε turbulence model and Z-G cavitating model. By the contrast of simulation and experiment of cavtitation in the steady state of vehicle, the model is proved to be right. Then, the paper simulates axisymmetric vehicle and the one which has the attack angle respectively in the steady state. It summarizes the changing law of cavitation and analysis hydrodynamic performance.Secondly, the paper builds the axisymmetric vehicle model and studies the vertical lunching problem of cavitation. Based the scaled model, experimental result is contrasted with the simulation. The model is proved to be effective in the unsteady situation. Then the paper simulated the process of going out of water axisymmetrically. It gets the forms of cavitation in different time during two periods of underwater navigation and time histories of the impact pressure at sample nodes. It completes research of cavitation corrosion. At last, the paper studies how the difference of speed influences the loads and cavitation.Thirdly, the paper builds the three-dimensional model and studier the vehicle that goes out of water at a attach angle. The paper studies the load around head exiting from water with an attach angle. It discusses the relationship between angle, loads of different surfaces and the time of cavitation corrosion. Then the paper builds the mesh model with multiple degrees of freedom. The paper analysis the process and get the underwater trajectory, loads and posture.Based on it, it discusses how the cavitation and transverse velocity influence the vehicle. The simulation provides reference for the engineering practice.Finally, the paper builds the three-dimensional model under the influence of waves. Firstly,the paper builds the numerical waves based on the theory of linear wave and Stokes. It uses the method of velocity boundary to simulate waves. The accuracy is checked by the comparison between theoretical and experimental value. Then,the second-order Stokes wave is decided to be used. And the paper analysis the hydrodynamic performance and attitude of vehicle with cavitation under the fifth wave level. At last, the paper explores how the level and phase position of wave influence the loads and attitude.