Precursors in two-phase detonation: Occurrence of a contact discontinuity

Abstract

This paper is concerned with detonation-propelled shocks (precursors) occurring in gas-permeable charges. It is shown that the basic aspects of the event may successfully be reproduced within a one-dimensional two-phase picture widely employed in the modelling of porous energetic materials. Precursor shocks are sustained by intense gasification of the solid phase, provided the ignition pressure (P_ign) exceeds a certain critical level. At high enough P_ign, the post-shock flow is found to acquire a contact discontinuity. Although this pattern is compatible with the associated self-similar solution, the question of the mechanism governing its formation remains open.

Keywords:

• precursors in two-phase detonation
• channel effect
• gas-permeable explosives
• detonation in tubular charges
• contact discontinuities in gas flows

Acknowledgements

Engaging discussions with Leonid Kagan and Peter Gordon are gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. A dynamically similar phenomenon has been identified in polymorphic transitions in crystals [6].

Additional information

Funding

These studies were supported by the US–Israel Binational Science Foundation [Grant 2012-057]; the Israel Science Foundation [Grant 335/13].