Limiting Conditions for Jet Formation in High Velocity Collisions

Abstract

The high velocity collision of two solids is discussed as a problem in compressible fluid hydrodynamics. Such collisions may conveniently be divided into jetless and jet-forming categories. A theory is presented which describes flow in the collision region for the jetless case and determines a critical collision angle (as a function of material velocities and equation-of-state properties of the materials) above which a jet must arise from the collision. The experimental study of solid collisions utilizes metal plates driven by high explosives, the impact of the plates being recorded with a high speed smear camera. Two experimental arrangements are used, and data for collisions employing Dural, mild steel, brass and lead are presented. Jetless and jet-forming collisions are observed, and critical angles separating the two types are compared with theoretical predictions. Agreement seems sufficiently good to indicate that the theory is valid.