Examination of coherency criteria for high velocity jets
Abstract
An examination of a coherency criteria for high velocity jets is discussed in this paper. An analysis of the classical Pugh, Eichelberger, Rostoker jetting theory is used to develop an equation that defines the maximum coherent jet velocity as a function of the liner material sound speed, the liner beta angle, and the magnitude and direction of the liner collapse velocity vector. The liner material sound speed is assumed to be the liner material shock velocity at the time of liner material collapse. This shock velocity is a function of the collapse pressure in the stagnation region and thus varies with time and position along the liner. The analysis indicates that coherent jets at velocities greater than three times the liner shock velocity are possible with some combinations of the beta and collapse vector angles while incoherent jets at velocities equal to two times the liner shock velocity could occur with other combinations. The objectives of this paper are to examine the theory used to calculate jet velocity and to develop a criteria for calculating the maximum coherent jet tip velocity.
 Publication:

Presented at the 12th International Symposium on Ballistics
 Pub Date:
 August 1990
 Bibcode:
 1990ball.symp.....M
 Keywords:

 Ballistics;
 Fluid Jets;
 Hydrodynamics;
 Shaped Charges;
 Shock Waves;
 Velocity;
 Algebra;
 Linings;
 Fluid Mechanics and Heat Transfer