Cavitation Caused by Explosive Shock Pulses Reflected from the Sea Surface

Abstract

The characteristics of shock pulses reflected at normal incidence from the sea surface are examined as a function of charge weight and charge depth. The reflected tension pulse possesses a number of prominent features such as an initial spike, which is considerably shorter than the incident shock pulse, followed by a plateau that becomes longer for shallower or larger charges. These differences between the shapes of the incident and reflected pulses are attributed to cavitation effects near the sea surface. The acoustic results indicate that cavitation takes place for charge depths considerably greater than the maximum depth at which visible effects are caused at the sea surface. The acoustic effects indicate a breaking tension at least a factor of 10 smaller than that indicated by the visible effects.