Geometric Modeling of Channel Height Effects on Detonation Propagation Behavior

This work presents a study on how channel height influences the macro-structure and propagation characteristics of a 2D channel detonation using the geometric model of Crane et al. [1]. The idea behind the study was to vary channel height, H, over widths where multiple cells exist in the transverse direction, but also over fine enough resolution to track effects of fractional values of nominal cell width, lambda, to channel height. Since the transverse array of blast kernels launch waves that interact with each other, the study was motivated by the question of whether wave interactions at different fractional H/lambda values influence macro-detonation characteristics, such as wave speed. It was found that multiple steady state solutions are possible for a given channel height. The wave mode that the system eventually asymptotes to depends heavily on how it was initialized, namely the number of initial blasts and their location. The key result of the study is that for a given number of cells, the average detonation wave speed drops monotonically with increasing H and that this dependency is purely monotonic. Increasing H also causes jumps in the number of stable cells and average wave speed increases at constant H for larger number of cells. This result is explained from geometric considerations and the fact that each blast wave speed decreases monotonically with time from when it originated. As transverse distance between blast kernels increases, it takes longer for these blast waves to collide, causing an overall slowing in average detonation speed.