Detonation shock dynamics modelling with arbitrary boundaries

Abstract

The Detonation Shock Dynamics (DSD) model can be used to predict detonation wave propagation in a high explosive (HE). The detonation wave is prescribed with a velocity that depends on its local curvature. Additionally, the angle between the wave and the HE boundary may not exceed a specified “boundary angle”, the value of which depends on the HE and its confining material(s). The level-set method is commonly used to drive DSD computation. Boundary conditions are applied to the level-set field at the charge edges to maintain the explosive boundary angle criteria. The boundary must be accurate and continuous across adjacent computational cells to achieve accurate and robust results. This is mainly an issue for mixed material meshes where the material boundary does not coincide with the cell edges. A set of volume fractions defines the amount of material in each cell. The boundary is defined implicitly by the volume fractions, and must be reconstructed to an explicit form for use in DSD. This work describes a novel synthesis of the level-set method and simulated annealing, an optimisation method used to reconstruct the boundary. The accuracy and robustness of the resulting detonation propagation along a mixed boundary are then tested.