Level 1 V.& V. Test Problem 10: Escape of High Explosive Products

Abstract

The Escape of High Explosive (HE) Products test is a hydrodynamics only problem designed to test the codes' ability to model the propagation of an unsupported, HE detonation wave. An ideal gas is used to model the HE. The detonation products expand to the right and interact at the left with a constant velocity piston. The choice of {gamma} = 3.0 and a careful selection of the piston velocity produces straight-line characteristics and makes possible the calculation of the exact solution. This problem tests the calculation of flow near a cavitation front where large gradients exist and is particularly difficult because both sets of characteristics become coincident at the front. Multidimensional Lagrange/ALE codes allow flexibility in constructing the computational mesh. For 2 and 3-D calculations, the ability of the code to maintain symmetry can also be tested. Eulerian codes may have difficulty implementing the constant velocity piston (perhaps an actual piston could be modeled). Many codes use a ''programmed burn'' model to represent the HE detonation wave. In this model, the velocity of the detonation front is precomputed. For these codes, only the self-consistent hydrodynamics occurring behind the detonation front is actually tested. Finally, practical problems are seldom 1-D. Modeling HE detonations in multiple dimensions introduces many more interactions and other possibilities than can be tested by this 1-D problem.