SUMMARY

Cavitation in water is generally undesirable since it causes damage to propellers, hydrofoils and other underwater structures in addition to generating considerable noise and vibration. However, it can be used to advantage for several applications in the case of fully developed cavitation, or supercavitation, in which the vapor cavity produced by a moving body is larger than the body dimensions. Cavitation occurs when liquid breaks down due to pressure reduction. Natural supercavitation can occur on a blunt body traveling in water at high speeds or it can be achieved at lower speeds with the aid of foreign gasses being injected into the low pressure regions to aid the cavity growth. Supercavitating torpedoes and projectiles utilize this phenomenon for drag reduction and stability, allowing high speed underwater flight. Such military weapons pose a threat to submarines, surface ships and shore targets. The objective of the proposed research is to determine, through both theoretical and experimental methods, if an acoustic countermeasure capable of slowing, diverting, or disrupting the stability of a supercavitating projectile can be realized. This countermeasure would use acoustic pressure to affect the supercavitation envelope in a cataclysmic or at least detrimental way and cause the desired effect of stopping or diverting the incoming weapon. Work thus far has been focused on designing and building an experiment to realize a supercavitating projectile in the laboratory environment and in finding valid theoretical and numerical models to predict and explain experimental results, both in the stages of achieving supercavitation and in the future disruption efforts.