Abstract: Based on the FLUENT software and the dynamic grid technology controlled by user-defined function, the supercavitation flows of the continuously fired projectiles were numerically studied to analyze the characteristics of supercavitating flows. The numerical results of the supercavity shape and the drag coefficient of projectiles are effectively consistent with the experimental results, which indicates that the numerical simulation is exact, and the drag coefficient of projectile presents an increasing trend with the decrease in velocity of projectile. The mechanisms of supercavitations of two and three continuously fired projectiles are studied. The change rule of non-dimensional length is concluded, and the variation curve of velocity in flow field and the velocity vector are analyzed. The results show that, after the supercavity fusion of two projectiles, a high velocity re-entrant jet and many vortices are found in the aft of supercavitation. The vortices can lead to the rapid collapse of projectile supercavitation, which also indicates the extreme instability of supercavitation. The drag coefficient of two projectiles can reach to the minimum value when the two projectiles enter in a supercavitation. When the supercavitations of two continuously fired projectiles pass through the disturbance field, the supercavitations are disturbed, thus resulting in the increase and decrease in their drag coefficients. Key

Key words: supercavitation, underwatercontinuouslyfiredprojectile, dynamicgridtechnology, re-entrantjet, dragcoefficient