Investigation of Interior Ballistic Initial Conditions in ALE3D for Blast Overpressure Analyses

Abstract

We explore two initial conditions on the same numerical grid to simulate blast overpressure at crew locations in the far-field. The first utilizes a 2D axisymmetric simulation mapped into a 3D quarter symmetry domain (2D-IC) as an initial condition for the exterior blast overpressure simulation. The purpose of this method is to reduce runtime from days to hours where the simulation lends itself to axisymmetric (i.e. the interior of a cannon). The second utilizes a full 3D quarter symmetry simulation (3D-IC) started from propellant ignition to propagation to the position of interest in the exterior of the tube. These results are then compared to experimental blast overpressure results for the same position. The conclusions from the study are that both the 2D-IC and 3D-IC are valid methods for numerically determining blast overpressure. However, the two initial condition approaches vary significantly compared to one another.