Design of the ventilation law for accelerated motion of supercavitating vehicle

A series of high-speed projectile experiments have been conducted to investigate the characters of natural supercavitation. The fitting formula of the dependence of the character parameters of supercavitation on the cavity number was obtained by the analysis of experimental data. Based on above formula and some reported empirical formulas, a ventilation law for accelerated motion of underwater supercavitating vehicle was designed. The design shows that during the progress of the velocity increasing from 25 m/s to 95 m/s, the volumetric ratio of air blowing into the cavity should change between 0.002 and 0.17 m/s, which ensures the cavity length increasing from 0.57 m to 2.24 m. About 95% area of the model's surface is enveloped by su-percavity when the length of the cavity increases to 2.24 m, and the effect of drag reduction should be in evidence in theory.