Experimental Observation And Numerical Calculation Of Supercavity Flow Of Blunt Body Under Different Inclination Angle Into The Water

When slender body navigating at a speed impact into the water from the air, its surface forms cavity flow. The classic fluid dynamics problems are more common in terms of military applications of each countries such as missile torpedo. However, the high-speed objects supercavitation into the water involves both surface and vacuolar interface free boundary, which is strong nonlinearity and transient characteristics, the existing theoretical analysis is not accurate analysis of the relevant physical processes. At present, a large amount of experimental data and numerical simulation studies is used to measure and forecast data. The situation of the research in our country needs more attention of various circles scholar.In this paper, experimental methods and certain means of visualization is used to observe cavitation flow process, of different types of blunt head at different angles into the body of water. And cavitation generated mechanism and the law of development is analyzed. The head type, slenderness ratio, the initial launch angle, initial velocity into the water on the influence of water into vacuoles were studied. Combined with numerical simulation technology, two special inclination angle into the water vacuoles is further analyzed. The main contents are as follows:(1)four different head type and three different aspect ratios of the blunt body into the water is analyzed. The head type (cavitator) effect on the the stability and vacuole morphology of the blunt body into the water is studied.(2)the impact of the the angle of blunt body into the water is made a corresponding analysis. By comparing and analysis, the greater the angle into the water, the smaller probability that the vacuoles trajectory offset. While the angle into water less than11°, blunt body movement is difficult to extend the line along the trajectory of the air, and is very prone to jumping behavior (pop-up water).(3) For the situation of same angle of blunt body into water, the impact of initial launch speed to the trajectory and of vacuolar morphology is analyzed in this paper, and the relationship between the initial velocity into the water and closed modes is also analyzed.(4) two special inclination angle experiments is carried out, and vacuolar morphology of different water depth is compared. The damage law of flexible free surface to vacuoles symmetry is studied. Also,by comparing process of three types of blunt head vertically into the water, the result that, flat and round cavitator vertically into the water ensures its stable operation in vacuoles inside, is obtained.(5)with numerical methods, further research of horizontal and vertical into the water cavity movement is done. By comparing simulation results, it confirms that, in the deep water depth, supercavity contour close is similar to a symmetrical oval, and vacuolar morphology meets logvinovich independent expansion principle. While in shallow water depth, flexible free liquid fhave a certain impact to cavitation shape.