| Air's density and viscosity are far less than water's, this led to the drag for motional rigid body in water is about 850 times larger than that in air. Application of supercavitating technology can change the water wich wrapped the vehicle to air, so the wetted area will achieve the minimum value, this fundamentally changed its resistance characteristic, and effectively reduce the underwater vehicle's drag ,greatly enhancing its speed. If the vertical movement underwater vehicle such as homing mine designed for the typical supercavitating structure, so that vertical movement in the water has a high rate of vertical movement of such underwater ,and will greatly improve its battle effectiveness. This paper, based Russian―Shkval‖supercavitation torpedo, designs a simplified model of the vertical movement underwater vehicle, and using the Fluent software makes the numerical simulation of vertical motion underwater navigation exercise during the multi-phase flow problems.First this paper has introduced the theoretical foundation about the problem of supercavitation, summed up the control equation of fluid dynamics, and introduced the related turbulence model, cavitation model, supercavitation thory foundation,and so on. In the premise of understanding the theoretical knowledge, application of Fluent software numerically simulated the influence about different launch speed, different depth of the vertical movement underwater vehicle which has the typical supercavitating structure on the flow characteristics and supercavitation characteristics in case of natural ventilation. The last chapter of this paper mainly have made an analysis on the differences about cavity characteristic, flow characteristics in case of initiative ventilation, when the vehicle has different vents position, different depth, different speed and different ventilation rate. And we have made an analysis on the influence of gravity to cavity shape in the case of different Froude number. |
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