The Escape of High Explosive Products: An Exact-Solution Problem for Verification of Hydrodynamics Codes

Abstract

This paper documents the escape of high explosive (HE) products problem and demonstrates the use of the problem for code verification assessment. The problem, first presented by Fickett and Rivard (1974, “Test Problems for Hydrocodes,” LASL Report, Los Alamos Scientific Laboratory, Los Alamos, NM, Report No. LA-5479), tests the implementation and numerical behavior of a high explosive detonation and energy release model and its interaction with an associated compressible hydrodynamics simulation code. The problem simulates the detonation of a finite-length, one-dimensional piece of HE that is driven by a piston from one end and adjacent to a void at the other end. The HE equation of state is modeled as a polytropic ideal gas. The HE detonation is assumed to be instantaneous with an infinitesimal reaction zone. Via judicious selection of the material specific heat ratio, the problem has an exact solution with linear characteristics, enabling a straightforward calculation of the physical variables as a function of time and space. Implementation of the exact solution in the Python code ExactPack is discussed, as are verification cases for the exact solution code. The problem is used to conduct code verification assessment on a Lagrangian hydrodynamics code.